Ian,
I believe this is related to Waypoints Missing after install of AIRAC from Navigraph Hub - #10 by VGuixer it has to be as this is the same problem im facing along with others - there’s about 3 or 4 different threads all with the same issue.
When you use Import from the EFB in 24, it says it’s successful but then if you check the flight plan it seems to drop waypoints or not set destinations/waypoints bascially meaning your flight plan is not imported over at all for example:
vs
This is when using this route for example:
No destination, no enroute - this only happened since the latest round of updates im 100% sure.
I can get around it as others have by uninstalling and re-installing but it’s a heck of a faff around.
Thanks - do let me know if you need any further information?