At sharp angles, or if the normal map is strong enough, light on PBR materials just seems to get culled at a certain point. This doesn't happen with specular+normal materials.
This happens on both vulkan and OpenGL, with up-to-date graphics drivers, on the latest official build.
OS: Win 10
GPU: AMD rx590 8gb
CPU: Ryzen r5 2600x
Spoiler: