I suppose this isn't exactly a bug as it seems to be an intentional feature that an event cannot overlap with the beginning or ending of and era in timeline, given that a notification indicates that's why I cannot arrange my timeline properly. However, I do not remember this being the case previously as I have a habit of using important historical events as the turning points in eras in most of my worlds' timelines. If I'm making a mistake I'd love to know what I'm doing wrong, but it seems to me that a historical event should not create a conflict with the beginning and ending of an era in a timeline? If this is intentional, it makes it almost impossible for me to create my timelines effectively.

When I try to make important historical events that explaining the transition between eras, it frequently will refuse to accept changes to dates within certain years. Sometimes the years it tells me are in conflict seem arbitrary and don't overlap with any start/end years for eras as far as I can tell.