[V21 Stable] Ground Combat - Periodically invisible and armor-changing enemies

[Planetus]

I've seen a lot of enemies (mostly sebillians and sometimes caesans) that, on one turn, seem to have basic clothing/armor and on the next turn have armor indicating a much higher rank. Now, on the final mission, I'm seeing enemies appear out of nowhere very near to my soldiers with lots of time for attacks (throw a grenade, take 2-3 shots, etc), indicating they haven't moved very far, but there was no way for them to get that close without being in my sight for a long range. These enemies have also never triggered reaction fire. This makes the final mission basically unplayable, as sebillians can close to short range without any risk of attack and then spend a whole turn blasting my characters apart.

[Planetus]

I've seen it again, and this time I bothered to get a screenshot with proof. The red tile cursor indicates an enemy, and the middle red enemy marker on the right brings me to that spot (no others are even in the same room), and last turn there was a sebillian who threw a grenade at me from there. In other words, there's an enemy there but he's invisible.

[ATTACH=CONFIG]Invisible Enemy[/ATTACH]