9To5Google reports that there’s no clear pattern to the bug, but it seems emails mentioning the date may have been the trigger.
Post Date – 11:45 AM, Sat – 12/24/22

San Francisco: Google Calendar, the time management and scheduling service of tech giant Google, is reportedly creating random events based on emails and newsletters from Gmail.
9To5Google reports that there’s no clear pattern to the bug, but it seems emails mentioning the date may have been the trigger.
A common event that some users have noticed is the “US Financial Privacy Notice,” which appears as an all-day calendar event and reminder notification on Android smartphones with the same title.
Additionally, the newsletter seems to have sparked the events as well.
On Twitter, some users reported this problem.
While one user said, “My @googlecalendar has started creating random events based on emails I receive, but it’s just random marketing content and newsletters”, another user commented, “Random bug in @googlecalendar ( ?). A bunch of random emails show up in my calendar as events.”
The exact cause is unknown, but users can fix the issue by going into their Google Calendar settings under Settings > Events from Gmail. Reports say this should stop events from being created when the “Automatically add events from Gmail to my calendar” checkbox is turned off.
