Gradient Sky Goes to Black After Adding a Terrain to the Scene

using HDRP version 8.2.0 - Unity version 2020.1.10f1

Steps to Reproduce: 1. create a new Scene with File > New Scene 2. select the Sky and Fog Volume GameObject in the Hierarchy 3. in the Inspector, click the New button next to Volume > Profile to create a new profile for this volume 4. add the Visual Environment override 5. enable Type and select Gradient Sky 6. enable Ambient Mode and leave on Static 7. add the Gradient Sky override 8. enable Top, Middle and Bottom 9. => so far so good, changes made to this override can be seen in the Scene editor 10. add a Terrain to the Scene

=> this is where things get weird... - double click the Terrain to center it, and you'll see it's glowing very brightly - place the Main Camera somewhere on the Terrain and the sky appears black

thought maybe something in the Terrain's Lighting settings was causing this, but changes I make here don't seem to have an affect on the Scene...

any ideas??