System Information
Operating system: MacOS Catalina 10.15.7
Graphics card: AMD Radeon Pro 5500M 8 GB, Intel UHD Graphics 630 1536 MB

Blender Version
Broken:

• 2.93 master 2021-03-31

Worked:

• 2.92
• 2.93 master 2021-03-18

Short description of error
Volumetric shadows disappear when looking towards a sun light, within around 45 degrees. Especially apparent when volume density is much greater than 1.
Point and area light shadows seem unaffected.

Comparison:

2.93 video example:

Exact steps for others to reproduce the error

1. Create a mesh
2. Add a principled volume material with density of 10
3. Add a sun light
4. Enable volumetric shadows
5. Enter EEVEE rendered view
6. Rotate the view to face the sun light, notice the shadows disappear on the volume.