I noticed that playback is ignored when a trill happens later on a tied note. Check out bar 2, beat 3 … half notes not played until the trill happens on beat 1 of next measure. UPDATE - this happens with both NotePerformer and HSSE.
Another thing I noticed is that the trill ends on the upper note, rather than the main (starting) pitch. I don’t see a way to alter this behavior. (Probably the same with REAL players). 
I ended up re-writing the part to be 3 separate notes - half note, half note with trill, followed by 8th note without trill. This gets me the sound I like, but not visually what I would prefer. (Third world problems 
). Anyone have any ideas?
trill.dorico (799.7 KB)
I don’t think there’s a good way to get the result that you want here without some monkey business, I’m afraid. You might find that writing the two half notes either side of the barline in separate voices and then joining them with a cross-voice tie (or even a slur) allows you to get a bit closer to the result you’re after.
Thanks Daniel. I appreciate the time you took to look into this. I will try that monkey business, as you called it - just to go down that path as an interesting experiment. What I ended up doing was printing the score as I wanted it to look, and exported the audio from the version that sounded as I intended. It just occurred to me that someone in the future might land on these posts if they search for “monkey business”! 
EDIT… I tried both cross-voice tie (first time doing this) as well as a slur between 2 different voices and they both work like a charm! I just wish I could get my players to end the trill on the starting pitch! Ha ha.
All the best!