System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce RTX 2070 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 451.77

Blender Version
Broken: version: 2.83.2, branch: master, commit date: 2020-07-09 05:50, hash: rB239fbf7d936f
Worked: (newest version of Blender that worked as expected)

Short description of error
If there are more than 4 alpha textures lined up in front of the view, cycles starts adding odd shadows to the alpha. Then after 9 layers a black box starts to appear. This doesn't seem to be a problem in EEVEE as long as shadows are set to cutout.

Exact steps for others to reproduce the error
Create a plane and add a material that has an alpha cutout applied. (2 examples in blend file.)
duplicate the texture and layer them one behind the other. Once you hit 4 you'll start noticing a soft shadow, where the alpha should be eliminating them, and once you hit 9 the soft shadow turns black.
Make sure that these layers are lined up in front of the view.

Thank you for your time...and if I'm just doing something wrong, I apologize. I tried every solution I could find online...none that went past version 2.80

Best
Andrei Feheregyhazi