Leap 15.2 - dovecot throws error "Invalid log_debug: event filter"

Hi *, after the latest update for Leap 15.2 I get doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf: Invalid log_debug: event filter: syntax error, unexpected $end, expecting '=' or '>' or '<' Reason is log_debug = source:sieve in conf.d/10-logging.conf After commenting out this line dovecot starts without any further errors. But why is this line a problem all of a sudden? I couldn't find any reason. TIA. Bye. Michael.