Android client doesn't start autosync on Android 8 and 9

I use the auto sync feature on my mobile for a long time already. I had some trouble first but finally got it working.

I now have Android 8.0 (Orio) and also another new mobile with Android 9.0 (Pie). Autosync worked on Orio but stopped working a couple of weeks ago. On Pie I configured the autosync as on the Orio mobile but didin’t get it autostart. On both systems manual sync works fine.

Seafile Android client version: 2.2.18
Seafile Server: 6.2.5 running on a Raspberry

Any hint what disabled autosync on Orio (Android 8.0) and why I don’t get autosync up and running on Pi (Android 9.0) is greatly appreciated.

Just another info: Mobile running Orio is a Samsung S7 which got some Android updates recently. May be there was some update causing the automatic sync to stop?

Autosync on Android 8 phones not working

I just described my issue in an already existing issue in github Automatic image upload broken which was created in April 2019