Why can't I reinforce some items?

The items that I cannot reinforce so far are the buckler shield, rapier and the daypack. There maybe more in either case I don’t know why I can’t.

Dont trust me on this, but i think like a month ago there was an update on how the reinforcement worked

I think the ability to reinforce non-cloth items was removed some time ago.

Well if that’s all then I have a LOT of materials to add.