I was using a scroll of monster detection on FGJC5 to see exactly what was guarding which artifact when afterwards I was given a prompt to teleport, but I didn't notice and pressed space. So i was randomly teleported and afterwards the endlessly scrolling messages were stuck like this.

(more) You pick up the metal cap. (flashing white square goes here)

Or

(more) you hit the lightning lizard and critically wound it. (flashing white square goes here)

I can only see the most recent thing that happened on any given turn. Using ctrl n m to switch the type of message display didn't fix it while it was in the drop down display, but it didn't seem to affect the two line buffer at the top display.



Edit : Saving and then reloading the game fixed it.