As stated as the topic, seemingly upgrading any piece of gear - whether it be a weapon or piece of clothing to max and then proceeding to upgrade the rarity on said equipment causes the game to crash.
I tried upgrading Johnny's glasses, with the Blue rarity to max and then tried upgrading it to Epic rarity - which causes the game to crash. I've done this to several Iconic weapons as well and the result is the same where I am forcefully booted of the game and is given an error message to send the crash report - I've conducted this several times in different circumstances and the result is the same no matter what.
I tried upgrading Johnny's glasses, with the Blue rarity to max and then tried upgrading it to Epic rarity - which causes the game to crash. I've done this to several Iconic weapons as well and the result is the same where I am forcefully booted of the game and is given an error message to send the crash report - I've conducted this several times in different circumstances and the result is the same no matter what.