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Is there a reason for this? Or is it an actual bug? I haven't received any downvotes recently, so that's not the issue.
Edit to include some questions from the comments below:
Re duplicate of this: I haven't deleted any posts recently, nor have any posts of mine been deleted, as far as I can tell.
IIRC, I have downvoted an answer (or question) before (at some point in time), but I'm pretty sure it's been at least 6 months :D. @Shadow Wizard said that maybe the answer I downvoted (-1) got deleted (+1), and then undeleted (-1). That's possible, I guess (I had thought that they expire after a while and only mods can undelete, but I guess that's not the case).
Aannd it just happened again. (Although as @Cai pointed out, I might have already gotten the +5 from this post so this might be a false positive (aha- see what I did there))