https://developer.blender.org/T77999
! In T77999#971427, @mano-wii wrote:
So if you want this option to work, you need to decrease the level of multires for the viewport or disable the multires.
This is really not intuitive, but it is not a bug
Disabling the multires does not work, only if you decrease the level to 0, but this is an additional action, which I consider absolutely unnecessary. Why not just do it automatically?