I just visited the question here, which is locked as a "community effort":
What is a historical lock, and what is it used for?
I (legitimately) wanted to "Follow" the question so that I would be notified if the status of those types of questions changed in the future.
When I press the "Follow" button, it appears to work. But then I notice a banner at the top of the page:
This post has been locked; locked posts can't be voted on
When I refresh the page, it's clear that the "Follow" action did not work.
Something's clearly wrong here. Ideally I would be able to follow the question. If not, the action button should not be available. And if I can click the button, it should show the correct error message.