What, exactly is this fighting? Some people think short chasing, some tufts of fur flying or shooing away from food is fighting. If they were actually fighting I assume you would have stepped in and your question would rather be if you should keep them seperated, not so much if you should seperate.
It can be that does don't get along, if you see that there is almost constant tension, lot of scuffles, no grooming or resting together it can be that seperating them is the best way for both. Like, if you've got two very dominant, pigheaded girls there. It also can be that they are sorting out their hierachy, which to some extent can be an reaccuring thing if the character match isn't ideal, but it really depends on how intense that is. My 9yo Fury and her 7yo daughter are such a pair, Fury is a absolut dominant character (although getting old now) and has to proof who's boss now and then, I need to feed the good stuff in different locations at those times.
At that age of yours, and this time of year you might see the worst of it now.
The setup is important, one hutch or cage that is too small and has no areas where they can get away from each other and out of sight would make things more difficult (The point of short chases is to make the other retreat, if there isn't anywhere to retreat to it could be percieved as an offense that she didn't leave for now, and escalate). I use two hutches per pair, connected with a tunnel, and a second level where they can get up. Also, they get a lot of garden time to work out.
If you don't have the space to seperate them, well, then that's maybe too little space for a duo thgat isn't a pretty perfect match.
If you seperate them now I doubt that chances are good to put them together later. I skipped most of these issues because my pairs are mother-daughter, I had 5-6 months to see which of the doelings got along best with mom.
If they really fight, seperate them. There is imminant danger of one being injured. But as I said, I can't tell if that is the case because some people percieve any not stereotyp peaceful bunny behaviour as fighting, some details of what they are doing would help.