Content Data Loss in Nextcloud Whiteboard

We have been using the Nextcloud Whiteboard app (version 1.0.5, AGPL-licensed) along with the configured and connected Whiteboard backend server running in container environments for some time now. While the setup and general operation have been stable, we’ve encountered a recurring issue involving content data loss.

Issue Description:

After a certain period of use, the content within Whiteboard documents (e.g., Example_Whiteboard.whiteboard) unexpectedly disappears. This leads to complete data loss for affected documents. Our observations suggest that this behavior frequently occurs after editing sessions via iOS devices.

Suspected Causes:

• We suspect the issue may be related to the WebKit engine, as Safari on iOS uses WebKit. However, the problem also occurs when using Firefox on iOS. Since all browsers on iOS are required to use WebKit, this points to a possible WebKit-related issue.
• It’s unclear whether this is a frontend problem (saving/syncing issues on the browser side) or a backend/server-side issue.

Observations So Far:

1. Content data loss typically occurs after prolonged editing sessions or periods of inactivity.
2. The issue has been reproduced in both Safari and Firefox on iOS.
3. We have not been able to replicate the issue on desktop browsers (Chrome, Firefox) or Android devices.

Questions/Suggestions:

• Are there any known issues regarding data loss in the Whiteboard app when using iOS browsers?
• Do you have any recommendations for configuring the Whiteboard backend to prevent this, or are there any known workarounds?
• Are there specific logs or debugging steps we should follow to identify the root cause of the data loss?

No files, tests, or entry points are named. Start by reproducing the data loss on iOS Safari and Firefox, then compare frontend behavior with the Whiteboard backend and collect the relevant logs; done means identifying and fixing the cause with reliable confirmation that document content is preserved.