Please help: They have started fighting....

My 2 male rabbits who have lived together for about a year, have started fighting and nipping each other.
Since Jazz was Neutered about 3 months ago, he has really calmed down and they have really bonded well, all snuggled up together ...its lovley.
But today i noticed that Harvey has been sitting in the corner of his run all day, this evening, i whent out to see them and harvey hopped up to me and was eating the grass i was feeding him and i noticed their was fur all over the bottom of the rabbit run....
I noticed Jazz and Harvey wont go near each other...If Jazz goes near Harvey, Harvey trys to nip Jazzs face , and if they go near each other, they chase each other all over the pen and pull each others fur out :O
They have been fine together up until now.
They have lived outside now for about 3 weeks now, before they lived in a bedroom inside.
Both are neutered. Jazz is about 1.5 and harvey is 4.5. I dont know what has started this as its only gone on for about 2 days at most...
Im worried they will hurt each other, they just dont seem happy anymore, and it make me sad to see them like this....
I dont know if this has anything to do with it, but Harvey seems more cuddly than usual, he is letting me pick him up and cuddle him, somthing he would tolerate before, but he would usually try and struggle after a while, where as he seemed to enjoy me picking him up for a cuddle today....
Appart from this they all seem ok, they are eating and drinking..

If anyone has any advise or ideas please let me know....

Hey,

Just thought i'd post and say i hope someone comes along soon. I have newly bonded buns but not come across this with them. Hope things sort themselves out.

Amy

Do you have other rabbits who have been near these 2 or have been in a similar area?

yes they live next to Micha and Lunar....but they always have done ....Lunar and Micha are fine with each other and they seem fine with Lunar and Micha...