This was LITERALLY mentioned in the latest patch notes actually, the one that came a few days before the launch of luxury stuff pack.
This is why I never accept ANY birthday invite. Also, having said that, it seems this was intended.
HERE ARE THE NOTES FROM THE MAY 14 PATCH:
What’s New?
Sims your household knows can call you up and invite you to some of their events!
Sims in a relationship might get a phone call to go on a date. Your child’s friends might ask them over for a play date. Or your “ready to age up, but not yet aged up” friends can call to ask you join them for their birthday party*.
*If you have aging turned off in the options panel, this will not invalidate that option. However, if you attend the birthday party, the Sim throwing the party will age up as a result of the party.
Just UGH EA just UGH
