https://wiki2.dovecot.org/Mountpoints

The list of ignored mount points are stored in a directory (/var/run) that's cleared on reboot. (On CentOS it's a RAM disk.) It seems this should be stored in /etc/dovecot to remain persistent across reboots.

https://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard

I discovered this when I saw a dovecot error message in /var/log/maillog that some of my automounts (that don't contain mail directories) were missing.

Latest dovecot from this distro is dovecot-2.2.10-8.el7.x86_64. Does the new release fix this? (I haven't seen any real problems from it, just log noise.)