I would like to add that you can't really get an ion burn from a misaligned ion trap magnet. The ions are already being deflected off to the side.
The magnet bends the electrons back towards the screen.
However, there have been reports (including photos) of a spot in a CRT with an ion trap.
So what's happening? After an interesting, lengthy discussion thread someone finally dug up the answer.
It can be caused when the electron beam is off target and vaporizes part of the metal gun assembly which gets deposited on the phosphor!
Full article here
https://drive.google.com/open?id=1K9...jecZNCIRLLU0nn