I have the same issue. I think that this bug could be similar to another bug discussed in http://dovecot.2317879.n4.nabble.com/auth-worker-Error-double-free-or-corruption-fasttop-td66230.html and was fixed by https://github.com/dovecot/core/commit/3c5101ffdd2a8115e03ed7180d53578765dea4c9.patch .
Would it be possible to use this fix here as well? Thanks in advance Regards, Petr Bitzan
