thank you wascal, it took me quite a while to realize
that it was the pitch parameter that was stopping the sample
trigs from sounding.

when the sample trig is p-locked to pitch and is getting muted,
if you look in the tracks recorder page, you can see the
sample trig tries to start, but gets cut off very quickly.

none of the other parameters seem to make this happen, only
pitch changes through p-locks or lfo.