Operating system: Windows 10 Pro 1903 (18362.356)
Graphics card: Radeon 5700XT
Broken: 2.81 (sub 11), branch: master, commit date: 2019-09-15 10:29, hash: 87c017985719, type: Release
Short description of error
Shadows not rendered when Motion blur enabled (cycles)
Exact steps for others to reproduce the error
As far as I can tell, this only happens on GPU rendered tiles. When rendering with CPU+GPU OpenCL scene, the tiles rendered by a CPU have shadows, tiles rendered by the GPU have not.
As you can see on the picture, there are no shadows. By rendering it again I watched which tiles are rendered by what device and I found out it is only GPU. Tiles render in same order every time, so the same spot on a image had no shadows rendered.
Image (I highlighted missing shadows):
Source of light: Sun and one other light