Interestingly enough, I think I found a Library-related bug. When I use the Library to quickly bring up a girl's level, the price for leveling them up normally seems to increase ridiculously. Because I'd been doing this exclusively before, I thought they were just unreasonably expensive. But after a Reset, I noticed that Erika, the first girl you get, is even cheaper than Helen by at least 2Q, when they're at the same level. However, Mavre, one of the new additions, was leveled up in the Library, and her price is now in the NONs. And she's at less than half the level of Erika or Helen. The Library is still the easiest place for me to level them up, so this bug doesn't really stop me, because of how I'm set up, but other people may find this bug extremely troublesome.
Interestingly enough, I believe I have found the maximum level that can be achieved before WP prices start super-inflation. Erika was able to reach Lv54947 before her price began going up massively for each level. After the WP price of a girl reaches 242Q, they begin increasing by at least 1Q per level, which becomes very expensive very quickly. Before that, it would take almost 100 levels to increase the price by 1Q. Still, almost reaching 55K wasn't bad.