Canvass Robe loses quest item status upon transmogrification

Mervyn

I wanted to transmog some stats onto my Canvass robe to enter the deep so I didn't have to carry a big robe around in my backpack.

However after transmogrifying onto it, it loses the quest item status and no longer allows you access to the deep

Expected Result: for the quest item status to remain OR for the transmogrification process to reject the robe as it already has a property (quest item)

For anyone who purchases the potion, please take note to avoid disappointment.