bun(s) nipping each other .. ?

hello all,

I have my two bun(s) ( male at 6 mos. and the female 2 n half yrs old ) bonded and looked like clear sailing

but yesterday I had them doing their bunny business out of the cage ... it seemed to me that they were nipping each other and would go their separate way(s) for a little bit. than after awhile it would start over again .. w/ that, I also watched them and noticing that my female bun is starting it .. ?? whats the deal here ?!?!

they both have been fixed and they share the same cage ... it would be a shame if they have to be in separate cage(s) and the bonding processes starts all over again =0/

Yup, my female does that to my male but he tolerates it. Then sometimes he mounts her face and she tolerates that. Overall they get along fine, they don't circle each other and I always watch their body language just in case. A nip or two here and there isn't a big deal. Is there anything different in their environment?

not really, recently moved ( like over 3 weeks ago, w/ a little bit smaller space ) overall little bit of a smaller space

they are out for 4 to 5 hrs a day ... along w/ their toy(s) and the tunnel