It seems that this happens when there's some event that starts before and ends after a number of other events, as you can see in the screenshot.
Hi, Are you able to email us the timeline file at firstname.lastname@example.org ? This will help us work out what the problem is. Jess
Thanks. I just sent it. Here's another example of the problem: [Screen Shot 2020-06-01 at 11](//muut.com/u/aeontimeline/s3/:aeontimeline:Cl2e:screenshot20200601at11.22.30am.jpg.jpg)