Hello David
I’ve looked into this issue, and discovered it is not limited to multisite. When users install The Events Calendars or Event Tickets, the other plugins you are seeing will be recommended in the Plugins ยป Add New ยป Featured area. The bug here is that it indicated the last update was 48 years ago, long before our company or the WordPress CMS were ever created. Ooops!
So – you can see our most recent updates at https://theeventscalendar.com/release-schedule/ and rest assured that we do update more than once every 5 decades.
I’ve flagged this as a bug, and you will be notified when a fix is available. However, as it does not impact the overall usability of our plugins, it may not be a very high priority issue to resolve.
Thanks
Courtney ๐