Download the licensee repro here - https://udn.unrealengine.com/s/contentdocument/0694z00000CXLxCAAX
Rebuild the lighting.
Light shows up on the landscape but not on the landscape spline, although it does occlude the spotlight.
Expected Result: Light should affect the landscape spline like it affects the landscape beneath it.
Actual Result: Light does not affect the landscape spline but does occlude to create a shadow on the landscape beneath.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-126270 in the post.