Notification feed `activities` empty when using `activityFilter`

[andrewmikhniuk]

Notification feed activities empty when using activityFilter

Description

When creating a notification feed with an activityFilter (e.g. Filter.greater on created_at), feed.state.activities is always empty in the SDK.

Without the filter, activities are populated correctly.

Steps to Reproduce

final query = FeedQuery(
  fid: FeedId.notification(userId),
  activityLimit: null,
  activityFilter: Filter.greater(
    ActivitiesFilterField.createdAt,
    DateTime(2026, 1, 31).toUtc().toIso8601String(),
  ),
);

final feed = client.feedFromQuery(query);
await feed.getOrCreate();

// feed.state.activities → [] (empty)

API Request

POST /api/v2/feeds/feed_groups/notification/feeds/{userId}

{
  "filter": {
    "created_at": { "$gt": "2026-01-30T23:00:00.000Z" }
  },
  "watch": true
}

API Response (truncated)

{
  "activities": []
}

Expected Behavior

feed.state.activities should be populated from the filtered response, consistent with behavior when no filter is applied.

Actual Behavior

feed.state.activities is empty when an activityFilter is provided.

Environment

• stream_feeds: 0.5.1
• stream_core: 0.4.0
• Feed type: notification