I'm not quite sure what to search for on this, but I noticed a little number on one (and only one, so I couldn't pinpoint a trend) of my flags in my flag history.
The text appears as follows:
title of question [closed] (1)
the flag was marked as helpful, the question was subsequently closed, yet a little (1) remains. I tried to see what that question had that the other questions did not, but moderator shut-down, specific tags, number of votes didn't matter. My only guess would be number of answers to the question? But I have no evidence for that. Does anyone know for certain?