My theory on this is that men exercise their beauty premium differently.

Attractive students receive a disproportionate share of peer resources. Whether through tutoring or people eager to carry them through group projects. The people who are both intelligent and attractive lead study groups and get mobbed by people who just want to hear them paraphrase and explain things. The act of paraphrasing and explaining and preparing to perform reinforces the curriculum and benefits them.

At face value, females are passive. Help pursues them and remote learning scenarios make this unlikely. Males are initiators. Even in remote situations, they're still going to video/conference call people and hunt down help. Arguably, in a lockdown scenario, they're going to have more one on one access to the peers willing to hold their hands. The intelligent + attractive males are still going to lead groups and repeat and ruminate on the curriculum.