Ok, I see. Yes, the fields are the same.
I'm not sure if the quality factor (Q) of the mode (from your eigenmode simulation) is strictly related to S11. The quality factor of the mode deals with energy that is already contained by that mode, whereas the S11 deals with the matching between your excitation source and that mode. I would expect them to be the same if there was perfect mode matching, but do you know that is the case?
Update:
In fact, reviewing your images, it seems that the eigenmode fields go to zero at the PML (where your waveport should be). Is your wave port exciting such a mode? (Are these magnitude fields at a certain phase, or complex magnitude fields?)