Steps to repro:

Open unity with DirectX 12 enabled (-allow-d3d12)
Open attached project

1. Open scene "Large Scene"
2. If you're in DX11 then hit play, if not switch to DX11 (it will probably crash though, so restart without DX12 for now)
3. Notice the unique shadowing on the left object.
4. Switch to DX12 & hit play
5. Notice the incorrect shadowing on the left object.

See image below for reference

Tested in 5.3x and 5.2x both reproduces with DX12