Can you upgrade to 2.2.36 or 2.3.2.1 and reproduce this issue? 2.2.13 is quite old.
-------- Original message --------
From: "Andre Hoepner - i.based: Systemhaus GmbH + Co. KG" <a.hoepner@ibased.de>
Date: 18/09/2018 16:17 (GMT+02:00)
To: dovecot@dovecot.org
Subject: dovecot (2.2.13) panic on imap-login from iphone se