This is becoming more of an issue as programs that have classically been Advanced (Rads/Derm/Neuro) are now wanting to switch to a categorical match. The problem is that the PGY-1 of the "Categorical Neuro" match is actually an IM year, which means that as the IM PD I would want absolute veto power over whom is ranked in a categorical match. I expect that many programs like this have both Advanced and categorical slots, and they invite people to interview for both without consulting IM. And then you get the message you received. I'm not defending this practice -- it would be more reasonable to alert applicants that the interview is for an Advanced spot, and that at the interview (or afterwards) it will be determined whether a categorical spot is possible.