Does the paternal granny take second place to the maternal granny? Ideally they should both be equally involved with the children, but it often happens that the paternal granny is sidelined in favour of the children's mother's side.
I know of several instances where this is the case and grannies are rivals for time spent with the children. It can be very upsetting for those involved, especially for the paternal granny who is often left out. A sad state of affairs but the children's mum is naturally going to favour her own mother when it comes to babysitting etc.
I'm not saying it's right but I do see it happening regularly.
sticky labels on apples - remove before washing!