When I craft an item, I can see my signature on it...but when someone else examines me, they can't see it. When I traded the item to someone else, they couldn't see the signature still, only a blank space where the signature should be, and when I examined them wearing it, I couldn't see the signature either.
When they traded the item back to me, I could see the signature again, but they still could not see it when I wore it.

I also noticed that SOME of the items I've bought off the market have signatures, but SOME only have an empty space where it looks like a signature should be.

There is obviously a problem here.