Android app text editor doesn't write changes to server filesystem

Describe the bug
Changes from the text editor in the Nextcloud Android app don't get synced on the server filesystem. But they show up in the editor on other devices.

Changing a file from the webbrowser makes it sync to the server filesystem.
Update 2024-02-14: See https://github.com/nextcloud/text/issues/5102#issuecomment-1944185020
In short: It's about timing between step 2 and 3. And it's also reproducible in a webbrowser.

Bug is probably a regression between Nextcloud > 25.0 and 26.0.9. Didn't recognized it in Nextcloud <= 25. See also: #4100

To Reproduce
Steps to reproduce the behavior:

1. Create a md or txt file. (should have 0 bytes)
2. Open the file in the Android app and add some text.
3. Close the file in the Android app.
4. File will still have 0 bytes. (visible via the files view in the Android app or a webbrowser, or directly on the server filesystem)
5. Open the file on another device or in the webbrowser and you'll see the text added via the Android app.

Expected behavior
When closing the editor changes should be written to the server filesystem.

Server details:
Tested with two different servers.

• server 1
  • Nextcloud version: 26.0.9
  • PHP Version: 8.2 (Debian-12)
  • Database: MariaDB 10.11.4 (Debian-12)
• server 2
  • Nextcloud version: 27.1.1.0
  • PHP Version: unknown
  • Database: unkonwn

Client details:
Tested with two different Android devices.

• Device: Fairphone 3+
  • Nextcloud app: 3.26.0
  • OS: /e/OS-12.3-s (LineageOS-19 based Android-12)
• Device: Nokia 1 (TA-1060)
  • Nextcloud app: 3.26.0
  • OS: Android-10

Start by reproducing the edit and close sequence with the listed Nextcloud and Android app versions, then read the linked update and comment about timing between steps 2 and 3. Trace the editor-to-server synchronization path; done means edits made in the Android app are written to the server filesystem when the file is closed.