Landscape splines crash when landscape mobility set to Movable

After looking through our svn repo and tracking down which commit caused this crash to start happening, I was able to find some repro steps. It looks like if you add a landscape to sequencer and give it a transform track it changes the mobility to movable (specifically in MovieScene3DTransformTrackInstance.cpp in UpdateRuntimeMobility). My artist said it’s likely he had auto-key turned on and accidentally selected/moved the landscape while he was modifying a sequence.

Repro steps for this:

  1. Create a new project.
  2. Create a landscape in a blank map.
  3. Add a spline with 2 control points.
  4. Create a sequence.
  5. Turn auto-key on in sequencer and move the landscape.
  6. Save everything (not strictly necessary but it will allow you to go straight to the crash on subsequent attempts instead of setting up the sequence track each time).
  7. Go to the landscape editor mode and try to move or add a control point.
  8. Editor crashes.

I’m attaching a sample project, a copy/paste of the call stack I get when it crashes, and my dxdiag. I’d provide the crash log itself but I can’t find it. According to A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums it should be in AppData but I don’t have a ReportQueue folder in AppData/Local/Microsoft/Windows/WER so I couldn’t find it.