Shot in the dark? Probably not in the course of the game-proper. Remember that while the in-game clock can go on for years, canonically it's only supposed to take place over a handful of months.
Gwyn has been telling herself since she was young that her mother selfishly abandoned her family. After telling herself that her mother was a bad person and they were better off without her for so long, that's going to be a hard preconception to buck. Never mind that the bad blood she was cultivating can only be expected to have grown stronger when she started lusting after her father, which would add another dimension to her anger and frustration: Her mother was not just a terrible person who abandoned her family, she was a romantic rival, and by all accounts the preferred one.
Intellectually, Gwyn knows that she and Garth are never going to be a thing, and that it's wrong for her to want otherwise. If your character's a masculine lupine and have grown close to her, she even acknowledges as much when she asks them to roleplay. However, that same roleplay also shows that knowing something in your head doesn't stop the heart from yearning for it. It's not much of a logical leap to assume that - emotionally rather than intellectually - Gwyn still wanted to believe that if she kept proving that she was better (by her internal metric) than her mother, that some day Garth would come to see her as a viable alternative, even if only as a consolation prize in light of a continued relationship with Gwyr being seemingly non-viable.
Cue the finale of Winter Wolf, wherein Gwyr comes back into their lives, to Garth and Garret's appreciation, and gets back together with Garth. In one move the hopes and presumptions she made about both her parents all come crashing down around her. Her mother is back, and not only is nobody angry about it, everyone is welcoming her, and Gwyr and Garth are picking up where they left off. It's a violation of everything she thinks she knows about her mother and a shattering of the wan hope that her father might some day return her illicit affections. So she doubles down, to the point that her first words to her mother practically treat her like her like the homewrecking mistress of her errant beau.
Point being that this likely a wound that - barring extreme and potentially tragic events - would optimistically take a few years to heal. Probably longer if she can't make a clean break from her daddy issues or at least refocus them on a healthier and more available outlet. So probably outside the scope of COC2's timeline.
