@VolvoGirl I think I figured it out. Her company issued her a W-2 in a non-standard format (It is from their HR software). The box is labeled 12A, which would make me think its a 12-Code-A. It's actually Box 12A-Code-DD.
A: Uncollected social security or RRTA tax on tips reported to your employer
DD: Cost of employer-sponsored health coverage
So, I think this is on me for not reading the form well enough, and them for using a non-standard home-made document.
