Bayes.lock Permission denied or No such file or directory

Using Debian Exim and Cyrus, if these error messages show up in syslog:

plugin: eval failed: bayes: (in learn) locker: safe_lock: cannot
create tmp lockfile
/nonexistent/.spamassassin/bayes.lock.hostname.28303 for
/nonexistent/.spamassassin/bayes.lock: No such file or directory

or

spamd plugin: eval failed: bayes: (in learn) locker: safe_lock:
cannot create tmp lockfile
/var/lib/spamassassin/bayes.lock.FQDN for
/var/lib/spamassassin/bayes.lock: Permission denied

then check the options in

/etc/default/spamassassin

OPTIONS="--create-prefs --max-children 5 -D --nouser-config --helper-home-dir -u debian-spamd
--virtual-config-dir=/var/lib/spamassassin"