Generational dysfunctional patterns continuing during pregnancy. Advice on how to navigate these emotions.

My family is highly dysfunctional and as a result my mum and I myself live many counties away from the rest of the family, with occasional meet ups. I’ve always had a good relationship with my mum until my pregnancy (first child, first grandchild and I am her only child). I felt that my mum wasn’t as involved and interested as I expected her to be and we resolved this with a lot of open and deeply emotional conversations. We decided to not continue with past generational hurt and move forward making healthy relationships for my child/future children. I am trying to maintain a healthy family relationship with some of my other family after advice from my mum that it would be important for my baby to have to option to know them. Dispute my previous hurt, I am open and frequently communicate with my nan and offer to see her, invite her to baby shower, keep her updated daily with my life etc. It seems to be going well and I’m pleased with giving her another chance from being almost estranged. My nan promised to come and see me and my new house before the end of the year, as she can’t make it to my baby shower. I send her my rota for the next few months and tell her I am open to seeing her whenever I am free and can make time for her. My nan is very busy so it’s difficult to make plans with her, with only 4/5 meet ups occurring in the past 10+ years since I became a working adult myself . But I get a message from my my mum that my nan and her have made a date to see each other for a spa day on a day that I’m not available, with less than a weeks notice without consulting me. When I inform her that sadly I can’t make it, my mum replies “your nan told me you weren’t free, sorry” (I only work 2 days a week so it’s not difficult to find days to work around me and my mum currently isn’t working, so it shouldn’t have been hard to find a date we are all free). So again I just feel hurt that I have been reaching out to my nan after this has been a painful relationship, but then my mum who I am very close with also decided to meet without me. My nan hasn’t come to visit us for many years (since I was 16, I’m now 29) so it’s hurtful that that was arranged without me. We have a group chat I try to chat with them daily in so it feels like it was especially concealed from me. How do I navigate moving forward, especially with my mum who isn’t usually a difficult relationship.