The foul by UVA was so obvious our players may have relaxed. The non-call led directly to the tying goal, with only minutes left to kill. Feel awful for our women.
I'm going from memory, but I think I have the details correct.
The ball was off a UVA player, and the PSU player was trying to shield it as it went out of bounds, so that PSU would have a goal kick. A UVA player attempted to run around the PSU player that was shielding, and got aside her, closer to the goal line than the PSU player was. At that point, there was some banging (so to speak), which would just be a legitimate shoulder challenge, and thus no foul. To protect the ball from the UVA player, the PSU player turned a bit so that she was between the ball and the UVA player. (At that point, it was questionable to me if the ball was even going to go out of bounds.) The UVA player continued her shoulder challenge, but since the PSU player had turned, it now became the UVA player's shoulder into the back of the PSU player. The PSU player fell down as a result of the contact, and since it was a foul from behind and not from a shoulder challenge, the call should have been a foul against the UVA player the spot, resulting in a free kick for PSU.
In situations where one player is shielding a ball, and the other player is trying to get to it, it's not uncommon for there to be some jostling. The refs expect that, and allow it to play out until one player exceeds acceptable actions, and creates an advance for them/disadvantage the other player. Plays where two players are involved in a shoulder challenge, and one player turns, are a challenge for refs, but most of the time they see that the dynamics have changed, and one player has committed a foul, and whistle it. On the play in question, the center ref was in a challenging situation, as the play took place right along the goal line, and it went from a legitimate shoulder challenge to a foul in the back quickly, and when it did the player that was fouled was between the ref and the player that committed the foul. In such situations, it usually becomes the responsibility of the AR (1 of the 2 refs on the side, who in this case was the closest ref to the action) to either signal the foul with their flag, or to verbally communicate over the comm system to the center ref that a foul took place. I don't recall if the AR was in the TV frame when the foul took place so I can't comment on whether or not they signaled a foul (which the center ref does not have to accept and call if they feel differently), and we'll never know what was communicated between the AR and the center ref over the comm system.
As you noted, the non-call did lead directly to the tying goal with just over 2 minutes in regulation.
The final result, and the non-call of the foul, do suck for PSU. UVA does deserve some credit, as they pretty much dominated the 2nd half, and a chunk of the two overtime periods.