Glitch: Undoing a move AFTER spotting an enemy

[the_Fifth_Horseman]

Found on Infestation campaign, first mission. Repro attached.
Just move the rightmost Marine four squares forward and you'll see an enemy to the left.
Now try to undo the move.
It's undone even though we have measures to prevent that exact sort of thing?!

Repro attached.

[Niklas]

We only clear the undo if you convert a blip.

[Niklas]

I'm not really sure how to fix this in a easy way and no one else has reported it as a bug. It is more in line with a cheat you can do on missions with no blips on scanner.

If the scanner was working you would see the enemy standing there in the corridor and you would like to be able to undo your move.

We're moving this into Future.

[the_Fifth_Horseman]

Thing is, in all other cases the user _is_ unable to undo the move.
Here, the prevention seems to have broken?