I realize this is an old post, but if you still have this laptop and still haven’t found a fix (or someone else has this issue):
From your photo, it appears that the bent metal tab isn’t one of the contacts from the connector. It appears to be part of the surrounding frame for the port that got bent down towards the connectors contacts. (It may be the ground contact that needs to touch the outside of the thunderbolt cable’s connector.) It appears to be short circuiting with the contacts in the center of the connector. I would try bending it up and trying to get it flush with the upper inside surface of the opening.