Quail chasing/playing with each other????

Hi there! I'm new to the quail community and I have absolutely no idea what this behavior is! I have two Japanese quails that I have no clue what sex they are. But one seems to be pouncing, flapping its wings, running around the cage and what it seems to be like encouraging the other to play. The other one sometimes also does this back to the other, but not as often. Not only that, but sometimes it seems like the quail that "wants to play" is also defensive about it's food. It will sometimes push the other one away so it can eat. The quail that has been pushed away is shy and sort of afraid to eat by the other, so it goes pecking at the ground. But it doesn't happen all the time, they usually eat together just fine. One of the quails (let's call it the problematic one) is also a lot more expressive than the other, is this so called problematic one fighting for its dominance? At the end of the day, they both sleep and cuddle next to each other perfectly fine. Do I need to separate them? They usually do not like to be separated and if anything it will cause them to be stressed.
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In addition to the problematic quail that has been pushing, playing and "fighting for dominance", it has also been seen running backwards really fast. I worry because I heard it could have knocked it's head on something and could die, but it's been weeks and it still hasn't died yet. It's in perfectly healthy shape. Is there anything I could do to help this poor fellow? He's really an oddball compared to my other quail.