Please, let me know if it's possible, cuz i can't reproduce it on the demo project.
The link line disappears when it intersects with another, should we somehow ignore this behavior (maybe it's some optimization)?
The line also connected to the intersected point by no reason.

We manually call the DiagramLink.UpdateFromPoints method (always when our link entity points were updated), which works as expected, but when crossing, it attaches the line to the nearest point and breaks the correct display of the lines.

For some reason cannot attach the GIF, so download it here: https://dropmefiles.com/S4NEg