SIL... am I overreacting.

My SO’s sister is about 14 weeks pregnant with her first, and has just had a gender reveal, only my partner and I were never formally invited.

I knew about it because on Tuesday his mom was upset that she had possibly upset the sister by saying she already had plans the coming Sunday when the reveal was. That was the first their mom had heard about the reveal and had a work thing on. The sister responded “oh well we will video it for you”. Their mom was hurt by this but accepted it’s their baby and they can do what they want.

I also got a text from the sister on Tuesday asking to borrow my letter board and to send it home with her mom. No problem I do that, but she didn’t mention at all what was being planned.

My SO got a text late Saturday arvo saying “swing by for drinks at 3pm if your free tomorrow”. We weren’t free at that late notice so couldn’t go, nor did the text actually say it’s the gender reveal tomorrow. My SO had assumed she wouldn’t go ahead with it without their mom being there.

Does anyone else feel like this is a really weird situation? I get it’s her baby, but both my MIL and SO are hurt by her actions. They were discussing it earlier, I’m keeping my month shut as I don’t feel it’s my place to openly say how shocked I am.