diff --git a/src/libs/ReportUtils.ts b/src/libs/ReportUtils.ts
index 9c6377474e78..77f01342ec3c 100644
--- a/src/libs/ReportUtils.ts
+++ b/src/libs/ReportUtils.ts
@@ -8429,8 +8429,8 @@ function getOutstandingChildRequest(iouReport: OnyxInputOrEntry<Report>): Outsta
     return {};
 }
 
-function canReportBeMentionedWithinPolicy(report: OnyxEntry<Report>, policyID: string): boolean {
-    if (report?.policyID !== policyID) {
+function canReportBeMentionedWithinPolicy(report: OnyxEntry<Report>, policyID: string | undefined): boolean {
+    if (!policyID || report?.policyID !== policyID) {
         return false;
     }
 
diff --git a/src/pages/home/report/ReportActionCompose/SuggestionMention.tsx b/src/pages/home/report/ReportActionCompose/SuggestionMention.tsx
index b69a26e5f90e..8127d26251ff 100644
--- a/src/pages/home/report/ReportActionCompose/SuggestionMention.tsx
+++ b/src/pages/home/report/ReportActionCompose/SuggestionMention.tsx
@@ -280,7 +280,7 @@ function SuggestionMention(
                 });
             }
 
-            const filteredPersonalDetails = Object.values(personalDetailsParam ?? {}).filter((detail) => {
+            const filteredPersonalDetails = Object.values(personalDetailsParam ?? {}).filter((detail, index, array) => {
                 // If we don't have user's primary login, that member is not known to the current user and hence we do not allow them to be mentioned
                 if (!detail?.login || detail.isOptimisticPersonalDetail) {
                     return false;
@@ -302,7 +302,9 @@ function SuggestionMention(
                     return false;
                 }
 
-                return true;
+                // on staging server, in specific cases (see issue) BE returns duplicated personalDetails
+                // entries with the same `login` which we need to filter out
+                return array.findIndex((arrayDetail) => arrayDetail?.login === detail?.login) === index;
             }) as Array<PersonalDetails & {weight: number}>;
 
             // At this point we are sure that the details are not null, since empty user details have been filtered in the previous step
@@ -334,7 +336,7 @@ function SuggestionMention(
         (searchTerm: string, reportBatch: OnyxCollection<Report>): Mention[] => {
             const filteredRoomMentions: Mention[] = [];
             Object.values(reportBatch ?? {}).forEach((report) => {
-                if (!ReportUtils.canReportBeMentionedWithinPolicy(report, policyID ?? '-1')) {
+                if (!ReportUtils.canReportBeMentionedWithinPolicy(report, policyID)) {
                     return;
                 }
                 if (report?.reportName?.toLowerCase().includes(searchTerm.toLowerCase())) {