Said Achmiz is looking into the Captcha bug, but I figured out a way around the problem. Commenting is working normally for people with an account, so I've set up a commenting-only account. It's named Commenter and the password is commenter. If you want to log in and comment, do so. I can't promise this will stay active forever, but it should let you avoid filling out the captchas.
May 09, 2020
Comments
Testing, testing, can we really unapprove other people's comments now?
Technically, you can, but I can see any unapproved comments and restore them. Also, please don't.
Looks like the problem's fixed!
So it does, yes. I'll leave the commenter account enabled, though.