There's also the fact that Sensei's revulsion to the idea of becoming a father is a central component of his personality that is addressed repeatedly throughout the story, which is a stupid character detail to add unless it's somehow relevant, and honestly, I think it's far more relevant than JUST the Ayane situation.
The game repeatedly brings up pregnancy as something that makes Sensei uncomfortable. At one point it's described as a feeling of physical illness. One of the "spooky" moments has a crying child playing in the audio. When a girl uses pregnancy or breeding as a sexy roleplay thing, it immediately turns him off.
Chekov's Gun: If you create a detail and constantly draw attention to it, it has to be relevant.
We have the flashback scene where Sensei and Maya where Maya talks about them both hating babies. A scene that takes place on the rooftop. And the rooftop is only used as a location immediately prior and during a reset.
Pregnancy is a core theme, and there's a very real possibility it was a pregnancy that prompted Sensei to jump off the roof at the start of the game.
Speculation: I very strongly suspect that all this is tied together. The rooftop is important to the story because that was where Sensei and Maya met up, and very likely where he impregnated her. And when he found out, where he jumped from.
And thus, it's where he's drawn when it's time to end a cycle and begin a new one. And anyone carrying his child is also drawn there.
This is why Maya's INCREDIBLY bitter about having to repeat the same 3-4 months over and over again, because it's the first half of a pregnancy that never ends. Infinite morning sickness. This would explain why she eats 2-3 times as much as the other girls. And most of the time when she's shown with a watermelon, she's holding it like a pregnancy belly. Since she was pregnant before this process began, when the world resets, she gets reset to early in the pregnancy, and remains on the roof.
But Ayane was no longer pregnant because her restore point, so to speak, is pre-pregnancy, so when the reset ends, she poofs back to where she should be.
It also makes me curious about the other time we see one of the girls on the roottop (Bluejay). This was a bit earlier before the reset of that cycle, so that could very well be an exception, but pregnancy+rooftop+jump feels awfully.....loop-like. And someone intervened pretty heavily in that scene to put her back on the roof, so it's possible her pregnancy was undone at that point by whoever intervened.