You did a massive re-watch of the series not long ago, so I'm sure you'll know this right off. Wasn't there some kind of fire or other accident that scarred Pam, she had to go in for some kind of facial reconstruction, and came out with a completely new face (as in, she was recast)? Then the "new" Pam was the one who ran off into the sunset, never to return? And didn't she have some kind of terminal cancer on top of the new face?
If that's the case, why would they bring Victoria P back, other than for nostalgia? If they were to bring the character back, why not go with the other actress?
That is assuming I'm remembering Pam's fate correctly. I may be thinking of another series entirely. Hmmm.