Assuming you have a closed in area for the rabbit to sleep and that that is where the babies are, it could just be that its getting accidently pushed out. However, you will need to keep a check on all the babies as sometimes, sadly, mum canreject one or all. How old are they now? There is no harm in taking a sneaky look once a day to check all babies are ok. If mum will let you of course, some can getting a little grumpy and go to bite, they dont mean any harm, just protecting their babies and will stop doing as babies start opening their eyes and moving about . You need to have as little contact as possible with the babies as mum needs to smell the babies and herself, not you. If you need to keep moving any back, do it as quickly as possible and try picking it up using some of the straw or shavings from the hutch. That way, the familiar smell of mum will still be on the baby.
You are doing the right thing because the baby needs the warmth of the nest and its brothers and sisters plus needs to be where mum can feed them.
Good luck, hope it all goes well. Oh, and congratulations lol