Chords in stum mode doesn't work

[lisan01]

I use Ample Guitar M Lite II and when I try to make some chords in stum mode only one string is playing or it's only stum noise/palm mute sounds. I have played around a lot with the settings and sequence but I can't figure out what I'm doing wrong or if it's the plugins fault. The chords that doesn't work are for example D5 and F# 5.

Anyone else who have had this problem? How do I fix this?