Data Loss when using iOS Document Picker Plugin (and no Wifi)

I develop a document based iOS app and have received a number of customer complaints that changes they have made to their document (using my app) have been lost. The documents are stored in Dropbox and accessed via the built in iOS Document Picker UI (iOS13)

I have managed to reproduce this? failure using a simple 'test app'.

The basic process is:

- Open the document in dropbox (using my test app)

- Turn off WiFi

- Make a change to the document and push the app into the background (wait for it to save) - then kill it.

- Restart the app and have it reload the last document (via an iOS security scoped bookmark)

- Make another change, push the app into the background, wait, kill it and relaunch.

- Repeat a couple of times and the document will revert to an earlier version.

This is a relatively 'real world' example (since iOS will kill background apps) and WiFi is often sketchy.

I don't expect anyone to be able to debug my issue given the above - but if someone from Dropbox is around then I can go into more detail (and provide example code etc.)

This doesn't happen on iCloud or OneDrive.

Thanks