I’m probably missing something here, as I have never used plugin grabber before (I know I suck, but I didn’t have enough spare time before, and I also needed multilayering before even trying to use it), anyway, when I try to grab one of Kontakt 4 built-in drumkits (for example: Central Stage Kit; you can reach it by opening Kontakt4 GUI, browse to to Factory Library => Band => 7 - Drumkits => Central Stage Kit.nki), only the bassdrum is used as a sample: for example, E-3 layer should be filled with snare samples, but in fact it is filled with high-pitched bassdrum (C-3) samples.
the instrument is used in the plain built-in configuration and it is only responding to a single MIDI channel (#1) events.
actually, some of the higher samples are rendered, but they are high-pitched as well (for example, G#4 is rendered using the correct sample, but it is pitched up, probably by one octave). Tweaking with sampling options changes the result but the general issue remains
for some reason I cannot understand, enableing Kontakt’s Release Trails (which should in theory play another sample when note-off command is sent, but the aforementioned instruments have no release trails, as far as I understand) for all groups solves the problem.
to enable release trails on Kontakt 4:
click on the “adjustable spanner” or “wrench” icon (well, the one on the left of the instrument name, with the shape of the tool you use to tighten bolts), press on the “Edit all groups” button which will appear a tht etop of the instrument editor, then press on the “Release trigger” button and you have done