zlib.read errors after upgrade from 2.3.15 to 2.3.17.1

After upgrading my mailserver from buster to bullseye and dovecot 2.3.15 to 2.3.17.1 I got the following errors: Jan 22 14:22:32 Warning: doveadm(user1)<2953060><49b0NRQF7GFkDy0ALVPUUA>: mdbox /local/mail/user1/storage: rebuilding indexes Jan 22 14:22:39 Error: doveadm(user2)<2953112>: dsync(

move more than one subvolder doesn't works

Our setup: 2 replicated dovecot 2.2.33.2 servers thunderbird client When I select more than one mail subfolder in thunderbird and drag & drop them to another subfolder only one subfolger is moved. In the following I can't move another mail folder to the first target. Any ideas why this hap