Is lack of grooming a problem?

Hi all, Cookie and Domino have been bonded for about a week or 10 days or so, and they get on great except for one aspect, Ive noticed the absence of grooming. They will both put their heads down, nose to nose with each other, both obviously expecting the other one to groom and neither do really. Is this a problem????

I believe this is a factor that caused the fight with our too.

it might not be, but if neither are accepting being dominated, it could be a problem.