Hello Skipb,
Thank you for using Apple Support Communities! I understand that you're missing events in iCloud Calendars used on multiple devices. You've come to the right place for help.
You may want to try and restore your calendar from a previous version of iCloud, then check if the events appear. The following support article will walk you through how to do so:
If you accidentally deleted your calendars, reminders, bookmarks, or contacts from iCloud - Apple Support
You can also follow the steps under "Reverse a restore" if the missing events do not appear. Let's also confirm your sync settings for the Calendar app on your iOS devices. Go to Settings > Calendar > Sync. Confirm there is a check next to the length of time you would like to sync events from. Let us know what happens from here.
Cheers!