I have copied this over from the behaviour forum as I really, really need advice.

Yesterday afternoon my buns were enjoying some time out in their run in the garden, binkying, eating lots of grass etc. I check on them periodically, just to make sure they’re ok and not diggin out or anything. They were absolutely fine for about two hours when the last time I checked on them I noticed they were grooming each other, they hardly ever do that when we are around so I stopped and watched them for a while as it was super cute! Then they started circling each other, each one trying to mount the other and just going round and round and round. Then the fur began to fly! I rushed over and banged on the side of the run, this startled them enough that they stopped and I was able to split them both up and bring them back inside. I put them in their free roam area and checked them both other, no injuries but Freya had clumps of fur hanging out of her. It looked like it was all her fur that had been flying as Merlin was totally fine.
I let them run in their free roam area for half an hour so I could keep an eye on their interactions together and they were acting totally normal. Flopping, zooms, binkies, nose touching when they passed each other. Seemed like they had forgotten their little squabble. As I write this they are snuggled up together in their cage like nothing happened.
Later on that night they were snuggled up together and grooming each other, the most affectionate I’ve ever seen them.
They’ve only been bonded and living together for about a month so I figure theyre still sorting out who is boss. Everyone has a lovers tiff at the beginning, right?

Well today they went out into the garden run again as the weather is good. They were fine for about half an hour and then they had another scuffle. I rushed out and managed to split them up. It seems to be Merlin who is starting it, he chases Freya around and they end up nipping at each other. Freya started screaming today I split them up for five minutes whilst I checked the both over for injuries but they are both fine, just a couple of clumps of Freya’s fur pulled out like yesterday. I put them both back in the run and watched them and now they seem fine.

I can’t figure out what is causing these fights! I had a few thoughts but none of it seems to make sense:
Food: they eat from the same food bowl and hay rack everyday without issue.
Space: the run is smaller than their free roam area indoors but it is bigger than both levels of their hutch combined.
Territory: the run was neutral territory to both of them the first time they ever went out there, we also move it to a new location for some fresh grass each time we put them out.

The only thing I can think could be causing this is hormones. Merlin was castrated 8 weeks ago and Freya was speyed 6 weeks ago. They’ve been fully bonded and living together for 4-5 weeks now. All I can think is that the hormones are finally starting to leave their systems and they have to get used to each other again, maybe they smell different now or something. But if this was the case surely the hormone levels change gradually, not just all of a sudden? They never ever scuffled before, not even during the bonding process.
Also it’s strange it only happens in the garden. Never in the house or in their cage. I don’t want to stop putting them outside as they love the sunshine and munching on the grass.
Please, please help!