Calendar bringing in stranger's appointments

Following up here in case anyone else ever has this issue. I have just gotten off the phone with Apple Support. Last night I cleaned up the last several years under the "Misc" calendar category, to redefine my own items as something else, leaving any items under "Misc" as belonging to the other unknown user. Today Apple Support told me that there was some kind of outage in this area (geographically) recently that affected Calendars, and that could possibly have something to do with it. It makes sense, since the unknown user seems to have a lot of business in my neighborhood. Today we just deleted the "Misc" calendar altogether and made sure my computer security had the highest level (it does - two-factor authentication). FYI to delete one of these calendar categories, press Control and click on that category, and a short dropdown will appear that includes the option to delete. That's all I got for now.