[edit] I just saw a new version 3.30.2 on Fdroid. This is what the changelogs says: Bugfix for two way sync. Please check listed folders in settings ā internal two way sync
I see exactly the same behaviour. LineageOS 21 and Nextcloud version 3.30.1. Today it consumed almost all my 4G data outside my home. On WiFi it consumed 102GB of data to my NC 29.0.8 server (which is completely isolated in a DMZ and only accessible through a tunnel). According to the Apache logs on the server the client seems to download continuesly the whole files section, over and over again. Note: AFAICS! Iām not a NC guru.
Richard.