For the past couple of days my comment counts have been acting strange. The number of comments beneath postings either doesn’t update or – even stranger – goes up and down at different viewings independently of the number of comments actually posted. For example, one of my posts has 11 comments, although sometimes the count indicates there are 8, 9, or 11. The comments are all there and they’re also listed in the “Recent Comments” section, but the little number seems to do what it wants.
This seems to happen every now and then, so don’t worry, it’s not just you. Your best bet is to send feedback to staff with details about what’s happening. You can send feedback through http://wordpress.com/contact-support/ once support is open.