scavenger -
if you’re in the companion inventory while it is looting you crash
if it loots something while switching tabs in you inventory you crash
if you loot the same enemy as the companion you crash
if it loots too far from you, you crash
medic -
not 100% on this one but my friend crashed when it tried to heal them without any healing items in its inventory
spotter - (not a crash but it will try to spot enemies way out of the fight, eg: fighting a tank at airfield, it will run to the other end to spot a runner)
spotting an enemy with binoculars at the same time as the companion and you crash
and using binocular spotting on an enemy the companion already spotted can crash you (subjective)
no module - (had no crashes so far but a few bugs)
companion shooting walls
companion getting stuck
companion not moving out of barbed wire
companion not shooting enemies
companion teleporting
companion causing fps drops