Displacement never gets updated when using the IR. It's by design.I got the advice to use C4D's Interactive Render Region for setting up displacement (in materials) which is not as convenient as the IR but works.CUMichael
In 3ds Max displacement does not get updated on camera movement, nor on changes to the material (except for changes in displacement settings). It is by design.
Yes, as i mentioned in my previous message, changing any displacement settings will update displacement in the VFB.