I think there are several reason what makes them wake up more frequently again!
Juleika eats only little solids, but still wakes more often during the night.
possibly they are eating to less, as they have to pay to much attention to their curiousity and new skills and as well they obviously train their new skills even when they sleep, so he just might wake up 'cos he starts to wiggle around!
I am not worried about it, don't make any attempt to force her to sleep through and let her wake as often as she wakes
