PDF highlight note blocks disappear after opening Capacities on tablet

I encountered a synchronization issue with the new PDF highlighting/annotation feature.

I created several highlights in a PDF using the Capacities desktop app. The highlights correctly appeared as note blocks in the PDF object.

Later, I opened Capacities on my Android tablet. Immediately after opening the app on the tablet, some of the note blocks generated from the PDF highlights disappeared. The same blocks also disappeared from the desktop app as soon as the synchronization happened.

However, the visual highlights themselves were still present inside the PDF on the desktop app. Only the corresponding note blocks were missing.

I was able to recover the missing note blocks by restoring an earlier version of the PDF object using Version History.

Both my desktop and tablet apps are currently updated to the latest available version.

Device information:

• Tablet: Samsung Galaxy Tab S7
• Model: SM-T870
• One UI: 5.1.1
• Platform: Android

Steps to reproduce:

1. Open a PDF in the desktop app.
2. Create multiple text highlights so that the corresponding note blocks are generated.
3. Wait for synchronization to complete.
4. Open Capacities on the Android tablet.
5. After synchronization, check the same PDF again on desktop.
6. Some highlight note blocks may disappear, while the highlights themselves remain visible inside the PDF.

Expected behavior: Opening or synchronizing the PDF on another device should not remove any highlight note blocks.

Actual behavior: Some note blocks associated with PDF highlights are removed during synchronization, while the underlying highlights remain intact.

Since the PDF annotation feature is currently in beta, this may be related to synchronization between the desktop and tablet implementations.