Probably old news to you log-addicts.
My back was turned for a few months executing duties, and G had the nerve to switch its site verification bot IP to 66.249.80.232 without telling me. This resulted in my sites losing their status as verified, because I have long blocked the irritating IP block used for Google Plus snippets
# Google Plus snippets
deny from 66.249.80.0/20 66.249.84.226 66.249.81.145
This line was blocking verification.
So I deigned to allow the bot's IP thus...
# Allow Google Site Verification bot
allow from 66.249.80.232
That got my main site verified, but not two others. To achieve verification on those, I had to remove my deny of 66.249.80.0/20 then they were verified.
Loss of verification happened mid June 2014, but doesn't appear to have affected our ranking in G serp.