Changes not saved from iOS to Nextcloud after creating a new file

Expected behaviour

When a new file is created from iOS, changes are saved back to Nextcloud automatically.

Actual behaviour

File creation is saved to Nextcloud, but all subsequent changes are lost.

Steps to reproduce

Use an application that creates new files and automatically saves changes, e.g. iA Writer

• Create a new file
• The initial save will appear in Files.app and is synced back to Nextcloud
• Continue working on the file
• No changes are saved
• Files.app and Nextcloud show that the modification timestamp is the same as the created timestamp
• Closing the file and re-opening loses all changes back to the first save point.

However, if I then re-open the file and start editing, changes are saved automatically and synced to Nextcloud as expected. So the problem only occurs in the same editing session as the initial file creation.

iOS version

12.1 (16B92)

App version

2.23.4 (4) from TestFlight

Server configuration

Operating system: Docker

Nextcloud version: 15.0.5

Reproduce the issue with iA Writer using the reported iOS and app versions, then compare the initial file-creation save with autosaves made in the same editing session. Trace the iOS file-sync path involved in creation and subsequent edits; done means later changes are saved and synced to Nextcloud without closing and reopening the file.