You know there is the tree points on every post and every comment where the further options like blocking, sharing, copying and so on is.
This menu doesnt show up when you click on a post you have already seen. This makes no sense as the menu us there on seen posts before clicking the post
I did some investigating: it seems that the menu (up/downvotes, save, reply and the 3-dot-menu) are extending to the right, off the screen, if there is too much in the bar.
Some examples where it did and didnt happen: