Rabbits chasing each other and mounting

I have one male lionhead and a female netherland dwarf, both sapyed/neutered, the same size, and they are bonded. The female is about 1 year old, the male about 9 months. These two bonded quickly, only took 4 days and the female has been pretty much dominant until now when she would hump him (usually his head) and then groom him - not sure if it is dominance and love? She is curious and he is generally placid

Usually they do everything together, eat, sleep, poop...they groom each other all the time. Usually the female grooms the male much more then the other way round. They have a cage with their litter tray, food, and water but they have a room to themselves with a bay gate to restrict access to the rest of the house when I'm not around.

However the last few days they have been chasing and mounting each other, hopping around each other and trying to take it turns to mount - she prefers to mount his head, he mounts her from the back. He is also nipping and pulling hairs from her. Thing is the next minute they are together lying side by side, sleeping or cleaning themselves as usual. Is this just typical rabbit play? They are both fixed so it would be dominance play but should I be worried that they are suddenly playing a bit rough? they have been inseparable all this time.

Welcome to the world of Spring Fever!

Rabbits hormone levels jump massively when the light changes at the beginning of spring, expect this to go on for up to a couple of months - keep a very close eye on them and if they scrap, you may need to reduce their space to calm things down a little.

Thanks! I thought that could also come into play since they seemed to be hopping around each in circles but since they are both fixed I didn't know if it was possible for hormones to be responsible.

Even when they are neutered they can still behave hormonally, but it doesn't usually last anywhere near as long as if they were not neutered. As they get a bit older they will most likely stop behaving this way altogether!