Actually Nathan is suffering from Boolean breakage today :)  That really
ought to evaluate false, but if you have Review= Owners (that is, the
plural form) then it would evaluate true.  The default from default.mailtpl
for that .bb command is actually

.bb ((&x ^= POSTMASTER) and (&x ^= OWNER)) and (&x ^= OWNERS)

So you may want to fix that first and see what happens.

Nathan