diff --git a/packages/stream_video/lib/src/sfu/data/events/sfu_event_mapper_extensions.dart b/packages/stream_video/lib/src/sfu/data/events/sfu_event_mapper_extensions.dart
index 198e2dd72..1eaf4ff51 100644
--- a/packages/stream_video/lib/src/sfu/data/events/sfu_event_mapper_extensions.dart
+++ b/packages/stream_video/lib/src/sfu/data/events/sfu_event_mapper_extensions.dart
@@ -248,7 +248,7 @@ extension SfuParticipantExtension on sfu_models.Participant {
       userName: name,
       userImage: image,
       sessionId: sessionId,
-      custom: custom.fields,
+      custom: (custom.toProto3Json() as Map<String, Object?>?) ?? {},
       publishedTracks: publishedTracks
           .map(
             (track) => track.toDomain(),