Sections in Volume Mode lagging ?

I have a larger BIM Model file in v19.
When I tried to switch a Plane Section to Volume Bricscad
lags for many seconds. Not only when editing the Section,
but everything. Loading File, View Navigation, ...
This happens for me on Mac, Linux and Windows.
Can't remember to have had this in v18 (?)

When I switch Sections back to Plane, everything is fine again.

Does that happen only to me ?