School mum making it clear we’re not invited to the party

[Thatbucketheadssong]

Just weird.

Mum at school, we’re friendly and chat, kids are friends etc.
She asked me at pick up if I was going to ‘X’s’ birthday party-other girl in the class, my Dd, 5, friends with her. It was the first I’d heard of it, felt slightly embarrassed, said ‘Oh I’m not sure, have to check my WhatsApp’s etc’ She then persisted with ‘Oh X’s mum sent me a message, some people invite the whole class on WhatsApp, others WhatsApp each person’ (yes, I know 😂) we’d obviously not been invited, bit 🤷🏻‍♀️But not too fussed really as our main larger friendship and mums/kids group is outside school and Dd wouldn’t know anyway at age 5 or be that bothered.
This mum clearly wanted to let me know…why? Was it being mean? I could see in her face she knew we weren’t invited, it wasn’t a casual oops mistake at all
Should I stay clear of this one?

In my experience mums at school are not like that atall. As you say it is very childish behaviour that I really don't recognise in real life. It's always mentioned on hear about avoiding class Whatsapp groups as they are full of arguments. Again, never seen that. In the whole of Primary I never saw one argument in the groups. I'm honestly baffled how anyone could start an argument about someone asking 'is it Christmas dinner day tomorrow?' or 'Ella says swimming isn't on tomorrow? Is that right?' 😂

Tbh it depends on the school.

First primary my children were at, no issue. Very relaxed parents, friendly. Social and chatty.

Second primary (had moved). Highly rated school, but... the most sharp elbowed set of parents and socially competitive people I had ever met. Lots of this kind of thing with competitive mothers. Hated it (but made some reasonable friends).

The difference was the aspirational culture. The second school was overtly like this with a lot of over involved parenting.