The Villager husk is the problem here. But only in ventures.
In deliver the bomb, all kinds of splash damage can damage the launcher through the walls. This include's exploding death bomb.
In repair/evacuate the shelter. The damage pulse modifier for mini boss can damage the shelter through the walls.
In all the missions, B.A.S.E take damage through the walls from any kind of splash damage. this includes exploding death bomb, mini boss's damage pulse modifier, lobbers and also those bone pitchers.
This is all i could replicate, for you u/Magyst.
You guys are absolute rockstars. Thank you. As much evidence as I can throw on the bug, the better.