Upvotes not staying

 Every single upvote I give does not stay. I've tried clearing my cache, giving upvote then refreshing (gone), giving upvote then waiting a minute before viewing the next pic and returning (gone), tried several upvotes on an image's comments (all gone when I return), tried only one or two upvotes on an image's comments (gone when I return or refresh)... The ONLY time I can get an upvote to stick is to upvote and refresh and repeat until it stays. This is getting tiresome. Tried Chrome, but I can't test there since I can't log in via FB.

Using FF (v16.0.2) with Adblock Plus