Michael,
Probably harmless, but I racked up about 450 of these overnight after
the upgrade to 2.7.0:
Jul 4 09:20:26 mx1 amavis[26145]: (26145-08) _WARN: Argument "x"
isn't numeric in sprintf at /usr/sbin/amavisd line 13126,<GEN11>
line 390.
It is mostly harmless: your tag level is undef and you don't have
the $log_recip_templ disabled. Instead of an '-' in the per-recip
log you'd get an empty string as a logged value of tag level.
Please delete or comment-out the line:
for ($tag_level,$tag2_level,$kill_level) { $_ = 'x' if !defined($_) }
at or near near line 13120 in amavisd.
Mark