Sculpt Hiding w/ fast Fast Navigate (bug?)

While in Sculpt Mode and using the “Fast Navigate” option…

Hiding a portion of your mesh (using H, hiding), if you rotate/zoom/pan your view, then it actually shows the entire (low res) mesh until you release the mouse button. This does not occur when using Alt+B hide method.

Speaking of Alt+B hiding, when using this method, the section of the screen that I have selected turns darker (no problem), but after rotate/pan/zoom of view, this “box” stays in the view and becomes very distorted. Strange… Also, this event is independent of fast navigation.

Not sure if they are bugs or not, but both of these are pretty visually jarring. Can anyone else verify this on their setup?

Alt+B is not really hiding. It just clips the view (the dark area is the area you have clipped)
Fast navigate drops down to the lowest subdivision when rotated so loses and hidden mesh at that moment
What you see is normal behaviour

Additional note : in sculpt mode, hiding with the H new function will improve performance a very lot at high polycount
view clipping with ALT+B does not improve performance in any ways.

yeah, i notice that alt+b is view clipping (hence why it makes a smoother clip of the mesh. but still wonder why the box distortion?