Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce GTX 980/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.07
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: rBf6cb5f54494e
when changing mulitres sculpt levels higher, the higher resolution mesh details are not recalculated correctly.
create a cube
add multires modifier
subdiv 6 times.
Set sculpt level to 6.
reduce sculpt level to 2
adjust with grab brush.
Set sculpt level to 6
notice polygonal artifacts have destroyed details.
looks like it's not calculating the higher resolution details relative to the limit catmull clark subdiv and is just using simple subdivision stored in object space without any relative wavelet compression at each subdivision.
(this fast resolution switcher addon I wrote highlights the problem even more)