diff --git a/src/App.vue b/src/App.vue
index ac50396e42..7430c5b86b 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -192,6 +192,11 @@ export default {
 		unsubscribe('notifications:action:execute', this.interceptNotificationActions)
 
 		window.removeEventListener('beforeunload', this.preventUnload)
+
+		EventBus.off('joined-conversation')
+		EventBus.off('switch-to-conversation')
+		EventBus.off('conversations-received')
+		EventBus.off('forbidden-route')
 	},
 
 	beforeMount() {
diff --git a/src/components/LeftSidebar/LeftSidebar.vue b/src/components/LeftSidebar/LeftSidebar.vue
index bb97ed0c34..1ceb2b94b7 100644
--- a/src/components/LeftSidebar/LeftSidebar.vue
+++ b/src/components/LeftSidebar/LeftSidebar.vue
@@ -675,7 +675,7 @@ export default {
 		this.debounceHandleScroll.clear?.()
 
 		EventBus.off('should-refresh-conversations', this.handleShouldRefreshConversations)
-		EventBus.off('conversations-received', this.handleUnreadMention)
+		EventBus.off('conversations-received', this.handleConversationsReceived)
 		EventBus.off('route-change', this.onRouteChange)
 
 		this.cancelSearchPossibleConversations()
diff --git a/src/services/EventBus.ts b/src/services/EventBus.ts
index 32f0dc3a56..6d9ac15fc7 100644
--- a/src/services/EventBus.ts
+++ b/src/services/EventBus.ts
@@ -11,9 +11,13 @@ type GenericEventHandler = Handler<Events[keyof Events]> | WildcardHandler<Event
 type ExtendedEmitter = Emitter<Events> & {
 	once<Key extends keyof Events>(type: Key, handler: Handler<Events[Key]>): void
 	once(type: '*', handler: WildcardHandler<Events>): void
+	_onceHandlers: Map<keyof Events | '*', Map<GenericEventHandler, GenericEventHandler>>
 }
+
 export const EventBus: ExtendedEmitter = mitt() as ExtendedEmitter
 
+EventBus._onceHandlers = new Map()
+
 /**
  * Register a one-time event handler for the given type
  *
@@ -27,7 +31,43 @@ EventBus.once = function<Key extends keyof Events>(type: Key, handler: GenericEv
 	const fn = (...args: Parameters<GenericEventHandler>) => {
 		// @ts-expect-error: Vue: A spread argument must either have a tuple type or be passed to a rest parameter.
 		handler(...args)
-		this.off(type, fn)
+		// @ts-expect-error: Vue: No overload matches this call.
+		this.off(type, handler)
 	}
 	this.on(type, fn)
+
+	// Store reference to the original handler to be able to remove it later
+	if (!EventBus._onceHandlers.has(type)) {
+		EventBus._onceHandlers.set(type, new Map())
+	}
+	EventBus._onceHandlers.get(type)!.set(handler, fn)
+}
+
+const off = EventBus.off.bind(EventBus)
+/**
+ * OVERRIDING OF ORIGINAL MITT FUNCTION
+ * Remove an event handler for the given type.
+ * If `handler` is omitted, all handlers of the given type are removed.
+ * @param type Type of event to unregister `handler` from (`'*'` to remove a wildcard handler)
+ * @param [handler] Handler function to remove
+ */
+EventBus.off = function<Key extends keyof Events>(type: Key, handler?: GenericEventHandler) {
+	// @ts-expect-error: Vue: No overload matches this call
+	off(type, handler)
+
+	if (!handler) {
+		EventBus._onceHandlers.delete(type)
+		return
+	}
+
+	const typeOnceHandlers = EventBus._onceHandlers.get(type)
+	const onceHandler = typeOnceHandlers?.get(handler)
+	if (onceHandler) {
+		typeOnceHandlers!.delete(handler)
+		if (!typeOnceHandlers!.size) {
+			EventBus._onceHandlers.delete(type)
+		}
+		// @ts-expect-error: Vue: No overload matches this call
+		off(type, onceHandler)
+	}
 }
diff --git a/src/services/__tests__/EventBus.spec.js b/src/services/__tests__/EventBus.spec.js
new file mode 100644
index 0000000000..35c87d6303
--- /dev/null
+++ b/src/services/__tests__/EventBus.spec.js
@@ -0,0 +1,283 @@
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+import { EventBus } from '../EventBus.ts'
+
+describe('EventBus', () => {
+	const customEvent1 = jest.fn()
+	const customEvent2 = jest.fn()
+	const customEvent3 = jest.fn()
+	const customEventOnce1 = jest.fn()
+	const customEventOnce2 = jest.fn()
+	const customEventOnce3 = jest.fn()
+
+	const testEventBus = (type, handlers, onceHandlers) => {
+		expect(EventBus.all.get(type).length).toBe(handlers)
+		if (!onceHandlers) {
+			expect(EventBus._onceHandlers.get(type)).toBeUndefined()
+		} else {
+			expect(EventBus._onceHandlers.get(type).size).toBe(onceHandlers)
+		}
+	}
+
+	afterEach(() => {
+		EventBus.all.clear()
+		jest.clearAllMocks()
+	})
+
+	describe('on and off', () => {
+		it('should emit and listen to custom events', () => {
+			// Arrange
+			EventBus.on('custom-event', customEvent1)
+			EventBus.on('custom-event', customEvent2)
+
+			// Act
+			EventBus.emit('custom-event')
+
+			// Assert
+			testEventBus('custom-event', 2)
+			expect(customEvent1).toHaveBeenCalledTimes(1)
+			expect(customEvent2).toHaveBeenCalledTimes(1)
+		})
+
+		it('should emit and listen to custom events with wildcard * ', () => {
+			// Arrange
+			EventBus.on('*', customEvent1)
+			EventBus.on('*', customEvent2)
+
+			// Act
+			EventBus.emit('custom-event-1')
+
+			// Assert
+			testEventBus('*', 2)
+			expect(customEvent1).toHaveBeenCalledTimes(1)
+			expect(customEvent2).toHaveBeenCalledTimes(1)
+		})
+
+		it('should remove listeners by given type and handler', () => {
+			// Arrange
+			EventBus.on('custom-event', customEvent1)
+			EventBus.on('custom-event', customEvent2)
+			EventBus.emit('custom-event')
+			testEventBus('custom-event', 2)
+
+			// Act
+			EventBus.off('custom-event', customEvent1)
+			EventBus.emit('custom-event')
+
+			// Assert
+			testEventBus('custom-event', 1)
+			expect(customEvent1).toHaveBeenCalledTimes(1)
+			expect(customEvent2).toHaveBeenCalledTimes(2)
+		})
+
+		it('should remove listeners by wildcard *  and handler', () => {
+			// Arrange
+			EventBus.on('custom-event-1', customEvent1)
+			EventBus.on('custom-event-2', customEvent2)
+			EventBus.on('*', customEvent3)
+			EventBus.emit('custom-event-1')
+			EventBus.emit('custom-event-2')
+			testEventBus('custom-event-1', 1)
+			testEventBus('custom-event-2', 1)
+			testEventBus('*', 1)
+			expect(customEvent3).toHaveBeenCalledTimes(2)
+
+			// Act
+			EventBus.off('*', customEvent3)
+			EventBus.emit('custom-event-1')
+			EventBus.emit('custom-event-2')
+
+			// Assert
+			testEventBus('custom-event-1', 1)
+			testEventBus('custom-event-2', 1)
+			testEventBus('*', 0)
+			expect(customEvent1).toHaveBeenCalledTimes(2)
+			expect(customEvent2).toHaveBeenCalledTimes(2)
+			expect(customEvent3).toHaveBeenCalledTimes(2)
+		})
+
+		it('should remove listeners by given type only', () => {
+			// Arrange
+			EventBus.on('custom-event', customEvent1)
+			EventBus.on('custom-event', customEvent2)
+			EventBus.emit('custom-event')
+			testEventBus('custom-event', 2)
+
+			// Act
+			EventBus.off('custom-event')
+			EventBus.emit('custom-event')
+
+			// Assert
+			testEventBus('custom-event', 0)
+			expect(customEvent1).toHaveBeenCalledTimes(1)
+			expect(customEvent2).toHaveBeenCalledTimes(1)
+		})
+
+		it('should remove listeners by wildcard * only', () => {
+			// Arrange
+			EventBus.on('custom-event-1', customEvent1)
+			EventBus.on('custom-event-2', customEvent2)
+			EventBus.on('*', customEvent3)
+			EventBus.emit('custom-event-1')
+			EventBus.emit('custom-event-2')
+			testEventBus('custom-event-1', 1)
+			testEventBus('custom-event-2', 1)
+			testEventBus('*', 1)
+			expect(customEvent3).toHaveBeenCalledTimes(2)
+
+			// Act
+			EventBus.off('*')
+			EventBus.emit('custom-event-1')
+			EventBus.emit('custom-event-2')
+
+			// Assert
+			testEventBus('custom-event-1', 1)
+			testEventBus('custom-event-2', 1)
+			testEventBus('*', 0)
+			expect(customEvent1).toHaveBeenCalledTimes(2)
+			expect(customEvent2).toHaveBeenCalledTimes(2)
+			expect(customEvent3).toHaveBeenCalledTimes(2)
+		})
+	})
+
+	describe('once and off', () => {
+		it('should emit and listen to custom events', () => {
+			// Arrange
+			EventBus.on('custom-event', customEvent1)
+			EventBus.once('custom-event', customEventOnce1)
+			EventBus.once('custom-event', customEventOnce2)
+			testEventBus('custom-event', 3, 2)
+
+			// Act
+			EventBus.emit('custom-event')
+			EventBus.emit('custom-event')
+
+			// Assert
+			expect(customEvent1).toHaveBeenCalledTimes(2)
+			expect(customEventOnce1).toHaveBeenCalledTimes(1)
+			expect(customEventOnce2).toHaveBeenCalledTimes(1)
+			testEventBus('custom-event', 1, 0)
+		})
+
+		it('should emit and listen to custom events with wildcard * ', () => {
+			// Arrange
+			EventBus.on('*', customEvent1)
+			EventBus.once('*', customEventOnce1)
+			EventBus.once('*', customEventOnce2)
+			testEventBus('*', 3, 2)
+
+			// Act
+			EventBus.emit('custom-event-1')
+			EventBus.emit('custom-event-2')
+
+			// Assert
+			expect(customEvent1).toHaveBeenCalledTimes(2)
+			expect(customEventOnce1).toHaveBeenCalledTimes(1)
+			expect(customEventOnce2).toHaveBeenCalledTimes(1)
+			testEventBus('*', 1, 0)
+		})
+
+		it('should remove listeners by given type and handler', () => {
+			// Arrange
+			EventBus.on('custom-event', customEvent1)
+			EventBus.once('custom-event', customEventOnce1)
+			EventBus.once('custom-event', customEventOnce2)
+			testEventBus('custom-event', 3, 2)
+
+			// Act
+			EventBus.off('custom-event', customEventOnce1)
+			testEventBus('custom-event', 2, 1)
+			EventBus.emit('custom-event')
+			EventBus.emit('custom-event')
+
+			// Assert
+			expect(customEvent1).toHaveBeenCalledTimes(2)
+			expect(customEventOnce1).toHaveBeenCalledTimes(0)
+			expect(customEventOnce2).toHaveBeenCalledTimes(1)
+			testEventBus('custom-event', 1, 0)
+		})
+
+		it('should remove listeners by wildcard * and handler', () => {
+			// Arrange
+			EventBus.once('custom-event-1', customEventOnce1)
+			EventBus.on('custom-event-2', customEvent2)
+			EventBus.once('custom-event-2', customEventOnce2)
+			EventBus.on('*', customEvent3)
+			EventBus.once('*', customEventOnce3)
+			testEventBus('custom-event-1', 1, 1)
+			testEventBus('custom-event-2', 2, 1)
+			testEventBus('*', 2, 1)
+
+			// Act
+			EventBus.off('*', customEventOnce3)
+			testEventBus('custom-event-1', 1, 1)
+			testEventBus('custom-event-2', 2, 1)
+			testEventBus('*', 1, 0)
+			EventBus.emit('custom-event-1')
+			EventBus.emit('custom-event-2')
+			EventBus.emit('custom-event-3')
+
+			// Assert
+			expect(customEventOnce1).toHaveBeenCalledTimes(1)
+			expect(customEvent2).toHaveBeenCalledTimes(1)
+			expect(customEventOnce2).toHaveBeenCalledTimes(1)
+			expect(customEvent3).toHaveBeenCalledTimes(3)
+			expect(customEventOnce3).toHaveBeenCalledTimes(0)
+			testEventBus('custom-event-1', 0, 0)
+			testEventBus('custom-event-2', 1, 0)
+			testEventBus('*', 1, 0)
+		})
+
+		it('should remove listeners by given type only', () => {
+			// Arrange
+			EventBus.on('custom-event', customEvent1)
+			EventBus.once('custom-event', customEventOnce1)
+			EventBus.once('custom-event', customEventOnce2)
+			testEventBus('custom-event', 3, 2)
+
+			// Act
+			EventBus.off('custom-event')
+			testEventBus('custom-event', 0, 0)
+			EventBus.emit('custom-event')
+			EventBus.emit('custom-event')
+
+			// Assert
+			expect(customEvent1).toHaveBeenCalledTimes(0)
+			expect(customEventOnce1).toHaveBeenCalledTimes(0)
+			expect(customEventOnce2).toHaveBeenCalledTimes(0)
+		})
+
+		it('should remove listeners by wildcard * only', () => {
+			// Arrange
+			EventBus.once('custom-event-1', customEventOnce1)
+			EventBus.on('custom-event-2', customEvent2)
+			EventBus.once('custom-event-2', customEventOnce2)
+			EventBus.on('*', customEvent3)
+			EventBus.once('*', customEventOnce3)
+			testEventBus('custom-event-1', 1, 1)
+			testEventBus('custom-event-2', 2, 1)
+			testEventBus('*', 2, 1)
+
+			// Act
+			EventBus.off('*')
+			testEventBus('custom-event-1', 1, 1)
+			testEventBus('custom-event-2', 2, 1)
+			testEventBus('*', 0, 0)
+			EventBus.emit('custom-event-1')
+			EventBus.emit('custom-event-2')
+			EventBus.emit('custom-event-3')
+
+			// Assert
+			expect(customEventOnce1).toHaveBeenCalledTimes(1)
+			expect(customEvent2).toHaveBeenCalledTimes(1)
+			expect(customEventOnce2).toHaveBeenCalledTimes(1)
+			expect(customEvent3).toHaveBeenCalledTimes(0)
+			expect(customEventOnce3).toHaveBeenCalledTimes(0)
+			testEventBus('custom-event-1', 0, 0)
+			testEventBus('custom-event-2', 1, 0)
+			testEventBus('*', 0, 0)
+		})
+	})
+})