Sometimes the owner and group of /var/lib/amavis/.spamassassin/bayes_toks change to root:root. This makes the cronjob fail:

Date: Sat,  6 Jan 2024 15:18:04 +0100 (CET)
From: Cron Daemon <root@octomain.octogon.de>
To: amavis@octomain.octogon.de
Subject: Cron <amavis@octomain> test -e /usr/sbin/amavisd-new-cronjob && /usr/sbin/amavisd-new-cronjob sa-sync

bayes: cannot open bayes databases /var/lib/amavis/.spamassassin/bayes_* R/O: tie failed: Permission denied
bayes: cannot open bayes databases /var/lib/amavis/.spamassassin/bayes_* R/O: tie failed: Permission denied

Manually restting to amavis:amavis allows the cronjob to run.

I have no idea what is changing owner and group, especially since the other files in /var/lib/amavis/.spamassassin/ are unchanged:

# ls -l /var/lib/amavis/.spamassassin/
total 19712
-rw-rw-rw- 1 amavis amavis 20406272 Jan  6 14:58 bayes_seen
-rw------- 1 root   root    5484544 Jan  6 14:58 bayes_toks
-rw------- 1 amavis amavis  2539520 Jan 25  2019 bayes_toks.expire4427
-rw-r--r-- 1 amavis amavis     1869 Jul 13  2014 user_prefs

The change happened at the same time as the last access:

# ls -l --full-time /var/lib/amavis/.spamassassin/bayes_toks
-rw------- 1 root root 5484544 2024-01-06 14:58:43.988842231 +0100 /var/lib/amavis/.spamassassin/bayes_toks
# ls -lc --full-time /var/lib/amavis/.spamassassin/bayes_toks
-rw------- 1 root root 5484544 2024-01-06 14:58:43.988842231 +0100 /var/lib/amavis/.spamassassin/bayes_toks