After getting my level five Psyker jacket I am unable to re-equip my prisioners shirt. Normally I would say this is a feature suggestion as I like the combo of a tee shirt with armored pants, but you can re-equip the prisioners pants. This leads me to think that you were either meant to be able to re-equip the prisioners shirt, or were never meant to be able to re-equip the pants. Just putting it out there, i would like to be able to re-equip the shirt if it was an intended feature like the pants.
Edit: also my cosmetics tab constantly shows a new item dot next to it, possibly the prisoners shirt?