Apple Calendar Won't Let me Edit

For years I've edited birthdays on my calendar (the date comes from contacts) to add a notification on the day of the birthday (default is the day before). It now won't let me, saying it is read only. It seems to have started this problem with Sequoia 15.0.1. Any suggestions?

I'll add a second issue. I use my Apple Watch to unlock my MacBook Air. Whenever I turn off my Mac and restart, I have to turn on unlock with my watch each time. That also is a new issue.