Have not read every thread so i dont know if the importance of this missing feature has been stated, but this problem results in me missing meetings, or being late.
What used to happen was, I get an alert 1 hour before, then I snooze it till say 5 minutes before (or whatever time depending on the nature of the meeting). Meeting not missed.
Now what happens is the notice pops up, and I either leave it there permanently but it overlaps on apps I am working in so its very very annoying, OR I click snooze but it keeps popping back every 5 minutes, so eventually I click the x icon and it closes but it does not come back. So meetings are sometimes missed. Big issue.
So as a 15 year plus Mac Calendar user, I now have to source an alternative Mac calendar app which has this feature.