I created an overview board with mirrored columns for project timelines. At one point the calendar view stopped showing the timelines and I do not know when or why. I’ve tried deleting and remaking the calendar view and toggling settings. Nothing has worked.
One of the connected boards did not have a timeline column. For some reason that caused the calendar to not show ANY timelines. Once I added a timeline column to the offending board the calendar started workig.