diff --git a/lib/Service/RoomFormatter.php b/lib/Service/RoomFormatter.php
index 90a1c20b16e..4430ccc3910 100644
--- a/lib/Service/RoomFormatter.php
+++ b/lib/Service/RoomFormatter.php
@@ -394,7 +394,7 @@ public function formatRoomV4(
 					$room->getRemoteToken(),
 					$room->getLastMessageId(),
 				);
-				$roomData['lastMessage'] = $this->userConverter->convertAttendee($room, $cachedMessage->jsonSerialize(), 'actorType', 'actorId', 'actorDisplayName');
+				$roomData['lastMessage'] = $cachedMessage->jsonSerialize();
 			} catch (DoesNotExistException) {
 			}
 		}
diff --git a/tests/integration/features/bootstrap/FeatureContext.php b/tests/integration/features/bootstrap/FeatureContext.php
index fb790f697ac..cc8ac557e00 100644
--- a/tests/integration/features/bootstrap/FeatureContext.php
+++ b/tests/integration/features/bootstrap/FeatureContext.php
@@ -460,6 +460,14 @@ private function assertRooms($rooms, TableNode $formData, bool $shouldOrder = fa
 			if (isset($expectedRoom['lastMessage'])) {
 				$data['lastMessage'] = $room['lastMessage'] ? $room['lastMessage']['message'] : '';
 			}
+			if (isset($expectedRoom['lastMessageActorType'])) {
+				$data['lastMessageActorType'] = $room['lastMessage'] ? $room['lastMessage']['actorType'] : '';
+			}
+			if (isset($expectedRoom['lastMessageActorId'])) {
+				$data['lastMessageActorId'] = $room['lastMessage'] ? $room['lastMessage']['actorId'] : '';
+				$data['lastMessageActorId'] = str_replace(rtrim($this->baseUrl, '/'), '{$BASE_URL}', $data['lastMessageActorId']);
+				$data['lastMessageActorId'] = str_replace(rtrim($this->baseRemoteUrl, '/'), '{$REMOTE_URL}', $data['lastMessageActorId']);
+			}
 			if (isset($expectedRoom['lastReadMessage'])) {
 				$data['lastReadMessage'] = self::$messageIdToText[(int) $room['lastReadMessage']] ?? (!$room['lastReadMessage'] ? 'ZERO': 'UNKNOWN_MESSAGE');
 			}
diff --git a/tests/integration/features/federation/chat.feature b/tests/integration/features/federation/chat.feature
index 08002cfce35..82971dbeb2d 100644
--- a/tests/integration/features/federation/chat.feature
+++ b/tests/integration/features/federation/chat.feature
@@ -138,6 +138,34 @@ Feature: federation/chat
       | id   | type | lastMessage |
       | room | 2    | Message deleted by author |
 
+  Scenario: Last message actor when the same user ID is present
+    Given the following "spreed" app config is set
+      | federation_enabled | yes |
+    Given user "participant1" creates room "room" (v4)
+      | roomType | 2 |
+      | roomName | room |
+    And user "participant1" adds federated_user "participant1" to room "room" with 200 (v4)
+    And user "participant1" has the following invitations (v1)
+      | remoteServerUrl | remoteToken | state | inviterCloudId                     | inviterDisplayName       |
+      | LOCAL           | room        | 0     | participant1@http://localhost:8080 | participant1-displayname |
+    And user "participant1" accepts invite to room "room" of server "LOCAL" with 200 (v1)
+      | id   | name | type | remoteServer | remoteToken |
+      | room | room | 2    | LOCAL        | room        |
+    Then user "participant1" is participant of the following rooms (v4)
+      | id   | type | lastMessage |
+      | room | 2    | {actor} invited you |
+      | room | 2    | {federated_user} accepted the invitation |
+    And user "participant1" sends message "Message 1" to room "room" with 201
+    Then user "participant1" is participant of the following rooms (v4)
+      | id   | type | lastMessage | lastMessageActorType | lastMessageActorId |
+      | room | 2    | Message 1   | users                | participant1       |
+      | room | 2    | Message 1   | federated_users      | participant1@{$BASE_URL} |
+    When user "participant1" sends reply "Message 1-1" on message "Message 1" to room "LOCAL::room" with 201
+    Then user "participant1" is participant of the following rooms (v4)
+      | id   | type | lastMessage | lastMessageActorType | lastMessageActorId |
+      | room | 2    | Message 1-1 | federated_users      | participant1@{$REMOTE_URL} |
+      | room | 2    | Message 1-1 | users                | participant1       |
+
   Scenario: Read marker checking
     Given the following "spreed" app config is set
       | federation_enabled | yes |