diff --git a/CHANGELOG.md b/CHANGELOG.md
index d8473e3c5..0e889ebef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,11 @@ nav_order: 1
 
 # Changelog
 
+
+## [3.13.3] - 2023-09-28
+
+- Fix `aiven_project_user` 409 error handling
+
 ## [3.13.2] - 2023-06-01
 
 - Improve Kafka Topic 404 error handling
diff --git a/internal/service/kafka/kafka_topic_cache_test.go b/internal/service/kafka/kafka_topic_cache_test.go
index 6b166888f..74cba56ce 100644
--- a/internal/service/kafka/kafka_topic_cache_test.go
+++ b/internal/service/kafka/kafka_topic_cache_test.go
@@ -35,6 +35,8 @@ func TestGetTopicCache(t *testing.T) {
 			&kafkaTopicCache{
 				internal: make(map[string]map[string]aiven.KafkaTopic),
 				inQueue:  make(map[string][]string),
+				missing:  make(map[string][]string),
+				v1list:   make(map[string][]string),
 			},
 		},
 	}
diff --git a/internal/service/project/project_user.go b/internal/service/project/project_user.go
index 41caa1eb2..0168ccae3 100644
--- a/internal/service/project/project_user.go
+++ b/internal/service/project/project_user.go
@@ -47,6 +47,16 @@ func ResourceProjectUser() *schema.Resource {
 	}
 }
 
+// isProjectUserAlreadyInvited return true if user already been invited to the project
+func isProjectUserAlreadyInvited(err error) bool {
+	if e, ok := err.(aiven.Error); ok {
+		if strings.Contains(e.Message, "already been invited to this project") && e.Status == 409 {
+			return true
+		}
+	}
+	return false
+}
+
 func resourceProjectUserCreate(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
 	client := m.(*aiven.Client)
 	projectName := d.Get("project").(string)
@@ -58,7 +68,7 @@ func resourceProjectUserCreate(ctx context.Context, d *schema.ResourceData, m in
 			MemberType: d.Get("member_type").(string),
 		},
 	)
-	if err != nil {
+	if err != nil && !isProjectUserAlreadyInvited(err) {
 		return diag.FromErr(err)
 	}