hi
i noticed this bug in both the Madmapper v5.7.x as well as in the v6 beta, screenshot attached.
setup is multiple outputs (lasers) and each has a mask applied (safety zones..). there is one laser material running, it renders 5 vertical lines, in a large quad covering all outputs. the masking should cut off the lines at the bottom, however it is shown correctly only on one of the outputs, the one edited last (on the left). the other outputs seem to not have a mask/safety zone applied! luckily this is a bug only in preview, not in the real output.
and even more limited: it is a bug only in the simple preview (let's call it "graphical preview"), not in the "laser beam preview"!
m