Operating system: windows 10
Graphics card: radeon rx580
when press Aplly Base button on multires modifier i get wired artifacts on my mesh. So without smoothing them i can't bake normal map from it
Exact steps for others to reproduce the error
Add monkey primitive, add multires modifier, make 5 levels of subdivisions, transform the monkey shape. Press ApplyBase button. Try to rotate the monkey to see artifacts. now this artifacts will be on all 5 levels of subdivision. You may make 6 level - those artifacts will be there to. If bake normal map from this highpoly mesh - all broken points will be on it.
I described this problem on reddit with screens https://www.reddit.com/r/blender/comments/di49w7/artifacts_with_28_and_multiresolution_modifier/