I tried to recreate this both on mobile and PC by commenting on a piece I uploaded and then trying to delete the comment. The delete button brought up the confirmation box no problem and the comment was able to be deleted easily.
I’m not sure if you’re deleting your own comments on images or other user’s comments, and your current platform could also be a reason (mobile or PC), those might possibly change things but I don’t know for certain. If you’d be willing, could you comment on this image post in my gallery below so I can see if the delete comment confirmation box breaks when deleting other user comments (this was the image I used to test)? Just type some random letters or something and post, it doesn’t need to be a specific comment or anything.
https://toyhou.se/4628764.taylor#34676079
EDIT: I have a content warning on my profile so clicking the link the first time won’t bring up the image, you’d have to accept the content warning and either refresh or close and reopen the tab