Currently Being ModeratedJan 14, 2013 4:21 PM (in response to kevinbrock)
I took one last look, and saw that the 'upgraded' version of amavisd.conf had a value for $sa_tag2_level_deflt in the format 'X.Y.Z', instead of a simple decimal number.
The value in the original amavisd was correct, but the upgrade process is broken somehow.
Changing it back to an X.Y value appears to have fixed the problem.
This is consistent with the type value of VSTRING that I was seeing in my debug output.