The airport is on the third DDS tile in from the scenery edge ( flying is still possible) - could this proximity cause this?
Remember that the height data points are Control-Vertices Spline data points. Not Fit Spline data points. So when you only have flattened the data points directly underneath the runway and not the data points in the vicinity, the runway can still have bumps. Especially if those far away points are way different.
This makes flattening in the CST:LE one of the most frustrating tasks ever by man created...
Especially if you want to make the airport as realistic as possible... If the airfield is very small and has a very curvy surrounding, I skip flattening more and more... Just use winch start or don't have a starting option and make/leave it a waypoint... Editing the TRN in Photoshop or other TRN editing program might be an option. But I don't like the Photoshop option and haven't found a good other program yet.
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