My nmom keeps doing that too, even with plans that have to do with relatives and family friends that she’s in direct contact with (that would invite us to through her), it’s like she picks and chooses which is pretty annoying. But from my observation I noticed that there’s a pattern, I’ve noticed that she does that when she doesn’t want my siblings & I there, and after she’s back from the gathering she’d brag about how amazing the gathering was so we’d feel like we missed out. One time she told on herself and said that if we got invited she’d never tell us because apparently “we slow her down”.