Calendar entries disappear

For the past 2 years, we have noticed that our future events get deleted sometime around the new year. We end up needing to go back in and recreate our camp out plan entries.

Is this there some sort of yearly clean up that is occurring? We need to figure out how to avoid having this occur every year.

That has never happened to either of the units that I deal with and have never seen a Community post about this before. Is it possible someone with Full access is changing the Meeting Schedules and not understanding what they are doing, or just deleting events?