I'm thinking the female is becoming aggressive towards the male because she's had enough of him, she doesn't want to mate, even though the male wants to, which is what I'm assuming, or maybe she just doesn't like him.
I kept a pair together for a few months and they showed no sign of aggression towards each other because I guess they were attached to each other. Keep in mind that quail can also be 'racist' among each other. My first male (roux dilute) was always aggressive towards my white quail and would chase the girls around and instead of mating, like he did to some hen, he would peck at them (definitely not a sign of affection), which is why he had to be separated. One of my other hens, when she was like 5 weeks old growing up with her siblings(brown) she would peck at anyone who wasn't her colour, but would leave her brothers (the ones that looked the same as her) alone. She got over it eventually.
Do they have enough room between them? Although quail are said to do well in small spaces, they really shouldn't. It adds onto stress.
Provide more hiding spaces, such as cutting holes in a tissue box, or adding branches to make the enclosure seem more natural can calm the quail down.
Its good that you're separating them for now. Keep an eye on the male though, when you get new females, if he still continues to be aggressive and pose a dangerous threat towards the females, then cull... You wouldn't want an aggressive gene in future generations.
