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 184.108.40.206 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 220.127.116.11/20 18.104.22.168 22.214.171.124
This line was blocking verification.
So I deigned to allow the bot's IP thus...
# Allow Google Site Verification bot
allow from 126.96.36.199
That got my main site verified, but not two others. To achieve verification on those, I had to remove my deny of 188.8.131.52/20 then they were verified.
Loss of verification happened mid June 2014, but doesn't appear to have affected our ranking in G serp.