in one document I've got a scratch orchestra set up; I put a series of chords into the trumpet part and the playback sounds polyphonically. In another document, similarly though differently instrumented (same project, different bit), I do the same thing and the playback attempts to play the chords as a solo line. I cut & pasted the sequence into the first violin line, and the same thing happens there. 

For playback I'm using VSL SE and Kontakt/Komplete 11   

(Finale 25, windows 10)