I’ll try to clarify:
I was able to reproduce this issue without any 3rd party scenery in the simulator. I also traced the error and was able to determine that the cause was this:
The panel was incorrectly trying to import an airway as a waypoint! There was a very obvious technical reason for this. It also explains why some routes would work while some would not - routes including airways would most certainly fail for anyone!
With the new version 1.2.5, the issue has been fixed!
Merry Christmas and a Happy New Year!
Kind Regards,
Malte