There is one user from another instance that I have Blocked, but their comments still show up in posts. I have tried unblocking and blocking them again, and their posts are hidden on their profile when blocked. Examples below are seeing their comment, clicking on their name, and seeing that they are already blocked. This is the only user where this is the case, and I've blocked their name and instance (not lemmy.world) but can provide it on request.
Is the kbin/mbin a known issue by chance? I would assume that going by user ID would work no matter the originating location, but maybe posts load differently than saved profiles.
I'm going to see if there is another user from the same instance that I can use to see if it is instance related. Thank you for the possible cause to look into.
Edit: so after further testing if the user comments on lemmy.world it is hidden, but their comments from other instances (checked their comments on dbzero and .ml when blocked/not blocked) show up. Blocks of other users appear to be successful across instances, so it looks like it could be the kbin/mbin federation. At least the block partially works!