Update: This morning, she did not unambiguously cry. She might have cried, but I can't tell; she tends to get manic around 11:20, but it's manic in the same way that small children are when they're overtired; she'll go from cheery to sobbing mess within 15 seconds with the right stimulus. Yesterday, it was Seth hitting her door with a curtain rod, and the day before that, it was a mean TTS about her friend dying. Today, I don't think there was any sufficient stimulus, but she still entered the same unstable state at the same time she had on prior mornings, so I think the phenomenon is still occurring, but timing her cries does not tell the entire story.
HOWEVER: She stated at around noon that she forgot to take her meds this morning, so there's a chance that the meds she takes in the morning are responsible for her crying routine, but I suspect she gets in that emotionally unstable state at the same time each morning, and only sometimes has a stimulus that sets her off. In any case, I will continue to monitor the situation and provide updates until either she is eliminated, or my theory is more conclusively invalidated.