Unity Terrain Tree Shadow Culling

Are there issues with unity terrain trees and shadows?
It works in the non-vr client, but as soon as I put my VR headset on, the shadow of any tree that falls out of sight also disappears, causing shadows to blink in and out of existence depending on where I look.
Here’s an example video I found where someone else has the same issue: Shadow of terrain flickering BUG in SteamVR - YouTube

If I can’t find a solution, I’d have to use prefabs for my trees, and that’d be a lot less performant, since then I won’t have billboarding of distant trees anymore.

Any help would be greatly appreciated.