so long as there isn’t anything other than None in the playback settings for each expression they should be interpreted correctly by HP so I’m at a loss. Can you post the file and note which measures are affected? Thanks.
I can't even check my work by listening back using that method (can't remember what it's called - SCRUB?) where you press CNTRL-SPACEBAR to hear the vertical entries (that'd be different on your MAC) or CNTRL-SpaceBAR-Shift to hear an individual part.
Even in that mode all of the string notes are just one pluck.
I sure hope you have an idea as to how to "un-stick" the strings from playing pizz for everything (even the whole notes!).
I took a look at your file and the pizz and arco seem to be playing back normally on my end. The exception being the staff with the String Bass assigned. Human Playback does not work as reliably with this instrument but, if you change the staff to the standard Double Bass, this will get better results.
Since you are not hearing any of the arco or pizz changes though, first make sure that you have Human Playback set to Standard (MIDI/Audio > Human Playback > Standard). Then try using MIDI/Audio > Reassign Playback Sounds and see if this clears up the issue for you.
Tom, I reassigned playback sounds and the cello seems to be playing pizz just fine there. Same with the contrabass. The issue is with the two violins and viola, and they get that pizz mark at the beginning of measure 1. You do have things set up correctly as best I can tell. I've also tried clearing MIDI data and that did not make any difference. What's really odd though is that violin 1 is doing it correctly. I deleted the pizz marking for those strings and then re-added it and no change.
I'm going to admit defeat at this point but you have David Cusick looking at it and you can't get any better than that. I'm not worthy ;-)