I recently saw this question and went to comment, only to find that there was no link to add a comment. See screenshot below:
This problem does not show up on other questions. I can't get to a computer to see how it works on desktop. Is the question protected in some way that blocks me from commenting, or is it a bug in the mobile app?
Edit: the mobile and desktop websites both say "comments disabled on deleted / locked posts / reviews," which doesn't make sense because it doesn't show up as deleted or locked.