Bug Pixel Displacement Depth Offset Shadowing turning off at runtime

Hello,

I have ground with pixel displacement + Depth Offset. At edit time, the shadows from the single directional light look correct. However, when I run the game, the shadowing on the ground from the depth offset height basically disappears.

Any idea why?

HDRP 2020.3.4f1. It happens with all post processing turned off. Essentially, why are the shadows changing as soon as the game starts? This is a test scene with zero code, so nothing should be changing when I hit play.

After playing around a bit, it looks like turning shadows on/off has a very minor change while playing. So the shadows _are_ doing something, its just a drastically reduced amount of shadowing compared to before I hit play.

[Edit-- added additional images for clarity]

 

It happens when the ground plane is flagged as static. If I turn off static, the shadows stay the same.