I noticed that whenever I upvote or downvote a comment while connected through Tor, my vote is silently ignored. I still get the "unvote/undown" button, but the user karma in their profile remains unchanged. I can repeat the same while connected through the clearnet, and everything works as expected: The karma of the affected user changes accordingly. The upvotes for the stories work fine though.

Is this a new defense from bots? Why does it affect established user accounts like mine? Has anybody else also noticed this?

Have you checked the network request and response? Is it as per non-tor

Maybe stale user profile pages are more likely to be served via Tor.

I've noticed that my upvotes and downvotes do not appear to affect comments like they used to, or at least there is now a delayed reaction to where I don't know if it's me or someone else voting.

I use Mullvad.