I suppose this is the cause why sometimes in base defense missions aliens spawns in living quarters, storage areas, or some other "safe" areas where they certainly should not spawn.
I'm not sure if I recall seeing this in XCF in particular, but in other mods at least.
I confirm, I have this issue in my mod when I play in Superhuman-Demigod
For modders, I noticed something
interesting (potentially, experienced modders know this already, but as I discovered it on my side...): I had an issue in my mod regarding base defense, where not all the aliens were able to spawn. And I noticed that those who were missing were systematically the 2x2 terrorists.
I tried to change the order of ranks (when declaring aliens in the alienDeployments section), and
specifying first the commander, then immediately the terrorists (then leaders, engineers, navigators and medics, and finally, soldiers)
fixed this issue
Now I still have the issue where aliens are generated in the Workshop, but from what I just read here from Meridian, this means there is no way to avoid it.