Family favouritism?

So growing up, it was always clear that my grandparents (on my fathers side) favourites were my cousins. They never outright said this, but it’s commonly known in our family, and it’s just something we don’t tend to talk about (I think we’re all so used to it that we don’t really care anymore). This really upset my mother when we were kids, as my grandmother would refuse to have one of us if she had one of my cousins (she said she didn’t think it was fair her attention was shared). She saw my cousins daily, but would only see us maybe once a month because she was always with them. So now my brother has had a baby, and I’m currently pregnant, there won’t be a year between our children and my mother is so excited to be a grandmother to both. But a few weeks ago, when my grandmother was visiting, she told my mother to make the most of seeing my brothers child now, as when I have my baby she will instantly be closer to it and there for will spend little time with my nephew (her reasoning was that because my sister in law isn’t a blood relative the connection won’t be as close as it will with my child which is basically the connection my grandmother has with my brother and I

). So to this, my mother flips her shit and tells my grandmother that she will never refuse to see a grandchild, will always have them together, and will love them equally which I 100% agree with.

I guess what I’m getting at is, does anybody else’s family act this way? Having favourites, refusing to see grandchildren together etc?