Doveadm backup stateful synchronization trouble

Hi,

The non-blocking error is: doveadm(user1s@domain): Error: Saved sync state is invalid, falling back to full sync: Invalid base64 data

This error occurs every time on my test machine (no traffic, only a few test messages). That error sometime also occurs on my production system, but not each time.

The command I used for the first time is : doveadm backup -A -s "" -d > state.txt After that there is a daily calls (as vmail user, my config only handle virtual users) to : doveadm backup -A -s "$(<state.txt)" -d > state.txt.tmp && mv state.txt.tmp state.txt

doveconf -n output is available at https://www.f-hamelin.fr/pub/doveadm-backup-doveconf.txt

Any help will be welcomed Best regards, Franck