When viewing the My Org Calendar or My Calendar tile from the Home dashboard, some calendar entries in the future are not visible. The entries are visible from the Journal Entry page however.
We limit the amount of data we display in the calendar tiles to only 6 months in the future. There is a lot of data being pulled on the Home screen so we limit this for page load performance. If you would like to see those calendar items, you should create a query to pull those futurecalendar items and then create a custom report to display them in.