9 month old naps once with my mother and twice with the nanny. Does the mismatch matter?

9 month old. my mother stays with us and a paid nanny comes on weekdays. with my mother he has one long nap after lunch. with the nanny it's two short ones. each pattern works fine on its own, and both of them are good with him. what i can't tell is whether switching between the two is the problem. the evenings he's a mess by 6 are mostly the days the handover happens in the middle of a nap. i'm at the hospital most of the day so i only see the end result. does a baby this age need the same rhythm every day, or is it fine for him to have 'amma days' and 'nanny days' as long as the overlap is sorted?