It tienes google accounts, probably from Gmail and you use any version of Apple Calendar, you may have timing issues. The information comes to us from US websites, so we do not know if it is a worldwide error or just a problem with certain servers.
For 24 hours there have been some synchronization problems with the information we have in the Google calendar and the information collected by the Apple Calendar application. It is also unknown if the error occurs in one direction or also affects the changes in Calendars towards the Google server.
It is not the first time that synchronization problems have occurred between Google services with Apple services. They are generally solved quickly in the first 24 hours of the error, more if possible if several users transfer it on social networks. This information is of great relevance for IT specialists who have to resolve the incident. Also indicate that the incidence affects Apple devices, both on the Mac, as on the iPhone and iPads.
Twitter is one of the social networks where users transfer these incidents to technical services. For example, the Twitter user, ian laverick. This user had 90% of the events disappeared on their MacBooks and had reported it to Google and Apple support. The user was relatively calm, as his events continued on the Google Calendar website. It is therefore a problem with the synchronization of the information.
At this time, in the Google and Twitter support forums, it is commented that the error should be in the Google servers. Be that as it may, we hope that the service will be restored soon so as not to create important incidents in professional sectors.