System Information
Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 416.94

Blender Version
Broken: version: 2.80 (sub 60), branch: blender2.7, commit date: 2019-05-08 23:54, hash: rB8f1951f555f5

Short description of error
in multiresolution sculpt mode the shader doesn't update if the mesh is in "smooth shade" mode.
In shade flat mode I noticed no problem.

Exact steps for others to reproduce the error

• create an mesh object
• turn smooth shade on
• add a multiresolution modfier
• sculpt

You will notice that the mesh is properly deformed, but the shader does not get an update until you go in edit mode or turn off/on the visibility of the modfier.

Please check the video to see what happen on my machine.

thankyou