And the bizarre behavior with the "huge final words" occurred withThat is truly weird.
In my email interface it is clear that one of those messages (#316) was sent as plain text. So how they could be displayed in Group_Help's Messages with variable text size is beyond my powers of explanation.
The other (#315) was sent as formatted text, but I don't see any formatting around the enlarged phrase "(web/email) unchecked." (although "unchecked" has <em>, so the italic is correct).
I don't see any connection to signatures though, neither message appears to have had one (from either email or the Subscription setting).