I just reviewed a custom flag on an answer that basically said it was not an answer. This answer had been deleted by review on April 29. The flag was raised today.
This is the second time I've had to deal with a flag that was raised on an answer weeks after it had been deleted by review. The first time was probably a day or two ago, and it was from a different user on a different post. I'm guessing the user didn't have 10k reputation either, but I'm not certain. I don't have the link to the first post anymore and I'm lazy to scour my browser history for it. Here's the post that was flagged today though. And a screenshot for the curious — you can clearly see it was deleted weeks ago:
Anyway, I declined the flag — because why in the world would you flag a post weeks after it had been deleted and forgotten?! — and then I found out that the user who flagged didn't even have 10k rep. So that makes this even weirder, because how was the user even able to see the post in order to flag it then (other than the stupidly unlikely possibility that they might have kept their browser open with that same answer for three whole weeks without refreshing or turning off their computer)?
In any case, if two separate users have managed to do this in two separate instances, then something is very wrong.