isInterior has to be added on every collision in order to make it work.

Tank has isInterior only in collision groups, and it doesn't work.
"collisionGroups": [
{
"isInterior": true,
"health": 4200,
"collisions": [
{
"pos": [-2.03258,1.0523,-1.21495],
"width": 0.1318,
"height": 0.78762,
"armorThickness": 2.0,
"heatArmorThickness": 800.0
},

AA has isInterior on both, collision group and on individual collisions and it works
{
"isInterior": true,
"collisions": [
{
"pos": [1.53705,1.42704,-3.71199],
"width": 0.11679,
"height": 0.86475,
"armorThickness": 9.0,
"isInterior": true
},

Franz just made so much collisions, that i didn't noticed group that did not have isInterior. It works fine.