what do you mean? like android might unmount part of the data while .stfolder is still in place so syncthing will propagate it as legitimate removal?
Anyway, so far my android seems to sync nicely.
And when we are already being offtopic, i’ve also added another syncthing node running on linux with ZFS, so i am doing snapshots every hour using znapzend. So far Syncthing+ZFS+Znapzend seems as perfect solution and i can highly reccomend it. I can sync between many consumer devices and have single znapzend server automaticaly keeping reasonable amount of history.
You can say that you want snapshot each hour for last 7 days, then each day for last two months and each month for last 3 years. Znapzend will then automaticaly create and delete old snapshots to keep just ones according to this plan. ZFS Snapshots are copy-on-write, so no extra space is used unless you actualy sync new contents. Also i run syncthing in container, which cannot modify snapshots, so even hacked syncthing will not be able to delete old snapshot. Very cool software stack in my opinion. Znapzend also can replicate snapshots to second linux server, but i don’t think that is necessary given i already have replicas in multiple syncthing devices in addition to ZFS.