There seems to be a problem (aren't there always?) in that in at least one case [Question: Why is absolute zero important?] the questions page shows 1 answer but if you go to the answer it shows 0 answers. Was the answer deleted and the count not updated?
Unfortunately, there are a lot of questions that match that description. To answer your question, no, I don't think the answer was deleted. As far as I've seen, deleted answers get an updated count too.
It has something to do with how some accounts are handled on the site. More specifically, with their status as active or banned. (Becca touched on this subject in her email on keeping Socratic safe).