diff --git a/packages/backend/migration/1747938628395-add-missing-indexes.js b/packages/backend/migration/1747938628395-add-missing-indexes.js
index 745b39c855..0229a6c898 100644
--- a/packages/backend/migration/1747938628395-add-missing-indexes.js
+++ b/packages/backend/migration/1747938628395-add-missing-indexes.js
@@ -4,19 +4,35 @@
  */
 
 export class AddMissingIndexes1747938628395 {
-    name = 'AddMissingIndexes1747938628395'
+	name = 'AddMissingIndexes1747938628395'
 
-    async up(queryRunner) {
-        await queryRunner.query(`CREATE INDEX "IDX_58699f75b9cf904f5f007909cb" ON "user_profile" ("birthday") `);
-        await queryRunner.query(`CREATE INDEX "IDX_021015e6683570ae9f6b0c62be" ON "user_list_membership" ("userId") `);
-        await queryRunner.query(`CREATE INDEX "IDX_cddcaf418dc4d392ecfcca842a" ON "user_list_membership" ("userListId") `);
-        await queryRunner.query(`CREATE UNIQUE INDEX "IDX_e4f3094c43f2d665e6030b0337" ON "user_list_membership" ("userId", "userListId") `);
-    }
+	async up(queryRunner) {
+		// Some instances have duplicate list entries
+		await queryRunner.query(`
+			DELETE FROM "user_list_membership"
+			WHERE "id" NOT IN (
+					SELECT MIN("id")
+					FROM "user_list_membership"
+					GROUP BY "userId", "userListId"
+			)`);
 
-    async down(queryRunner) {
-        await queryRunner.query(`DROP INDEX "public"."IDX_e4f3094c43f2d665e6030b0337"`);
-        await queryRunner.query(`DROP INDEX "public"."IDX_cddcaf418dc4d392ecfcca842a"`);
-        await queryRunner.query(`DROP INDEX "public"."IDX_021015e6683570ae9f6b0c62be"`);
-        await queryRunner.query(`DROP INDEX "public"."IDX_58699f75b9cf904f5f007909cb"`);
-    }
+		// Some instances already have these indexes, for an unknown reason
+		await queryRunner.query(`DROP INDEX IF EXISTS "public"."IDX_e4f3094c43f2d665e6030b0337"`);
+		await queryRunner.query(`DROP INDEX IF EXISTS "public"."IDX_cddcaf418dc4d392ecfcca842a"`);
+		await queryRunner.query(`DROP INDEX IF EXISTS "public"."IDX_021015e6683570ae9f6b0c62be"`);
+		await queryRunner.query(`DROP INDEX IF EXISTS "public"."IDX_58699f75b9cf904f5f007909cb"`);
+
+		// Now the actual migration
+		await queryRunner.query(`CREATE INDEX "IDX_58699f75b9cf904f5f007909cb" ON "user_profile" ("birthday") `);
+		await queryRunner.query(`CREATE INDEX "IDX_021015e6683570ae9f6b0c62be" ON "user_list_membership" ("userId") `);
+		await queryRunner.query(`CREATE INDEX "IDX_cddcaf418dc4d392ecfcca842a" ON "user_list_membership" ("userListId") `);
+		await queryRunner.query(`CREATE UNIQUE INDEX "IDX_e4f3094c43f2d665e6030b0337" ON "user_list_membership" ("userId", "userListId") `);
+	}
+
+	async down(queryRunner) {
+		await queryRunner.query(`DROP INDEX "public"."IDX_e4f3094c43f2d665e6030b0337"`);
+		await queryRunner.query(`DROP INDEX "public"."IDX_cddcaf418dc4d392ecfcca842a"`);
+		await queryRunner.query(`DROP INDEX "public"."IDX_021015e6683570ae9f6b0c62be"`);
+		await queryRunner.query(`DROP INDEX "public"."IDX_58699f75b9cf904f5f007909cb"`);
+	}
 }