I think DD is scooting around on her butt instead of crawling. I've only seen her actually go a couple of inches, but there have been a few times where I set her in her PnP with toys while I get some chores done and then come back to find her on the opposite side sitting up. DD is a champion sitter, but she can't rollover yet because she hates laying down so I'm pretty sure she's not crawling. She can also pull herself up to standing, but I definitely know she doesn't walk over to the opposite side. Do some babies scoot and just skip crawling?
Re: Anyone have a baby who scoots?
I actually told DH the other night that I was afraid DD2 is heading down this path. Much like your lo, she is great at sitting but hasn't rolled nor does she like being in her stomach.
I know a few babies, including my little brother who did/do that. It's actually kind of efficient because they can use their hands while moving around!
And yep, some babies do skip crawling altogether!
This is DD, too. She has rolled tummy to back, most of the time I think it was on accident. She has no interest in rolling back to tummy. She's a good sitter, though. Glad to read that other babies are like mine.