Guild Wars 2

The white mantle scroll cannot be upgraded to an infused variant in the mystic forge. While this may be intended, the fact that it’s the only LS3 back item with this behavior would imply otherwise.

it’s not intended, they are “investigating” it, god knows how many more months it’ll take for them to fix it, better to accept your loss and farm the bitterfrost frontier backpack. It would be lovely for once if they released stuff that worked properly.