There's enough plot holes and inconsistencies in Eddings' stuff that I think the mind shies away from looking at them. Here's the retcon on Polgara and her dad.

Original: They both loved Beldaran more than each other, and she hates him for marrying off her twin while keeping her as an apprentice, marked as a sorcerer to toil on their task for centuries, robbed of the only person she ever truly loved and by that task and immortality unable to ever love anyone else, except him and his crotchety immortal brethren.

BoS retcon: She disliked him from the outset and grew to loathe him for drinking and whoring around in his grief while she and Beldaran had no parents and that same grief. She resents that he clearly loved the mother she never knew and her sister more than her, and clearly feels a distant third place as one of the three women in his life and the only one still alive, and she knows it is so because she feels the same way. In there family of four, she and Belgarath clearly are their least favorites.

PoS: Her anger at her father is explicitly laid at the feet of sharing her mother's mind and her resentment at being left alone while pregnant. This is kind of necessary, if bizarre, since it is hard to justify being angry at your dad when he's in mourning for a woman you not only know isn't dead but talk with every day. You'd expect her to have guilt and anger over not being able to tell him and sympathy at how he is being cruelly deceived.

That's how I read it anyway.

Plus PoS has this new factoid that Polgara slavishly obeys her mother as a wolf pack thing, which would be fine enough if throughout the books they hadn't just implied Belgarath was the pack leader but actually said that when Polgara was in wolf form she obeyed her father more instantly and meekly. When Polgara shows up as a wolf in SoD to not startle her still disguised mother as wolf, this is pointed out. Apparently she's meek with her mother, a more senior pack member, even in human form, but not with her father, the most senior pack member, in human form. Eddings' stuff is riddled with things like that but this one really sticks out.

Pretty much only the twins fail to find a love interest in the end, I suppose coming up with a pair of immortal chicks for them would have been too tricky. Although maybe Polgara's twins are daughters, its never said and she certainly has had a lot of son-substitutes but no daughters, there you go, even the twins get paired off but not for another couple decades.

Poledra's resurrection was handled horribly, but acceptably, in Mallorean. Belgarath never talks about it in BoS and that absence makes sense, it hurts too much for him to think about it even with her back. Any inconsistencies during the stories he ignores, he can't bring himself to examine them. He could have done that with Polgara too but instead he writes her into Polgara and Beldran's life in a big way. So that her 'death' actually only effects one person, Belgarath. If he were going to retcon to have Polgara know her mother he should have started in BoS with an acceptable "The book of Alorn mentions my wife dying while giving birth but actually...."

I don't know why he felt obliged to resurrect her, but having done so he should have come up with something better like Zedar or Ctuchik capturing her and placing her in some sort of Ba'alzamon style prison which let her get out in spirit on occasion, then breaking down after their deaths. The way he handled it simply comes of a bit contemptuous of the readers.