Stoneware Jug Signed C.F.Chang Student Piece?

Picked up a mixed lot of pottery at a local auction yesterday an amongst the items was this, in my opinion, nicely made jug. Judging by the handle and the base I'm assuming that this is by a student potter but one who, again in my opinion, has some skill which just needs some refinement. Interesting that one of the glazes on one side has blistered while the opposite side is ok, due to the positioning in the kiln?

It does look like a student piece to me. That handle is particularly weak, and the glaze is too bubbly to be professional

It would be nice to know the story behind the piece, the rest of the lot were professional pieces so I wonder how this came to be part of the previous owners collection.

Could the mark have been scratched in after firing (and not necesarily by the maker) ?

It might have been made by a relative