Line connected to items is at the wrong position

[oulfik]

Describe the bug
I am using React (16.8.6) with timeline-plus (2.3.7). If you add an icon as a content for all items, the line that is connected to the icon box will be at the wrong position.

provide a simple example
https://codesandbox.io/s/react-example-5mtmk

Expected behavior
The line should always be attached to the middle of the icon-box.

Screenshots

Browser
Bug occurs in Firefox (68.0) but not in IE.

Additional context
If you click on an item and zoom in or out, the line will re-attach to the correct position. So a workaround for this problem would be a function that clicks on all items and then zooms in a little bit.