The problem here is with the calendar.  The calendar actually automatically requeries the models used as EventSources - using the date ranges provided by the calendar page itself.  This is disconcerrting when you go back to a table built on the same model and find that items that were not in the date range have dissapeared. 

Our best practice reccomendations is that you use different models for a table of events and for the calendar display. 
- The table should be set up to load data on page load and use any conditions you want applied. 
- The calendar model should be set up NOT to load data on page load.  This means that when the calendar tab is selected the model will load and grab events that are relevant for the time period the calendar is displaying. 

Cheers. 

Thanks Rob.

I have made the changes as you’ve described and it appears to have fixes my issue. Thanks

However… It appears to have flagged something else. If I add 3 or more Event Sources using the same model (the newly created ‘Cal-only’ model) they don’t appear on my calendar. 
If I revert back to only 2 Event Sources using the same model the events appear without issue.

Is this expected behaviour? 

Generally we reccomend having each event source tied to a separate model.  Multiple models can be tied to the same S-Object.  But having the Event Sources connecte twice to the same model will produce unexpected results.