Calendar won't sync with iCloud after macOS Tahoe update

Weirdly, my iMac iCal won't sync with iCloud after adding a new event UNLESS I change the calendar the event belongs to - then it syncs the event without problems. If I simply add the event, it doesn't sync it to iCloud until I change the calendar the event belongs to. Once it syncs to iCloud any changes to calendar or other details of the event sync normally.

[Re-Titled by Moderator]

Original Title: ical sync errors after installing tahoe