Attachment Viewer (Attachment-Focused Layout) — Attachments Not Fully Loading on Initial App Launch After October 2025 Update

[rwygmans]

After the October 2025 ArcGIS Online update, which introduced the modernized Attachment Viewer interface and new filmstrip gallery, I noticed that the attachment-focused layout does not load all attachments within the map extent when the app first opens. Only a partial set of attachments appear until I scroll through the gallery or zoom/pan the map—then the remaining attachments load.

The same hosted feature layer (56 points with photo attachments) worked fine before the update, and the map-focused layout still loads all attachments correctly. The issue appears limited to the attachment-focused layout after the October 2025 release.

Environment:

• ArcGIS Online (AGOL)

• Hosted feature layer with 56 point features (each with JPG attachments)

• Attachment Viewer Instant App created after the October 2025 update

• Tested in Chrome and Edge (same result)

Steps to Reproduce:

1. Create a new Attachment Viewer Instant App using the attachment-focused layout.

2. Use a hosted feature layer with photo attachments.

3. Launch the app.

Observed Behavior:

• On first load, only some attachments display.

• Scrolling or zooming triggers additional attachments to appear.

• No console errors appear.

Expected Behavior:
All attachments should load upon initial app launch without requiring map or gallery interaction.

Notes:

• The issue does not occur in the map-focused layout.

• This seems to be a regression introduced with the new filmstrip gallery and modernized interface described in Attachment Viewer: A New Attitude by Sarah McDonald.

Workaround:
Use the map-focused layout, which continues to display all attachments correctly on initial load.