That is a great question - my guess is that they will just revert to the standard YC Core terms, given that YC states in their Fellowship terms that they are hoping that Fellowship companies will then also go through the YC core program.

Put a different way, I am assuming that YC believes that a company that also goes through the core program would have a higher chance of success, so they would not want to provide a disincentive that would reduce the chance of a Fellowship company also going through YC core...