I sometimes get that myself. Other times it suppresses the midi output for that channel. Don't have a clue why.
I just go into my Midi player (Kontakt) and mute that instrument/s. No biggy, unless you can't get at the channels.

If you discover why it does this post in this thread so the other tech dummies aren't so lost.

BTW, this new version is really a big step it seems. The Tracks load fast and sound great.

I'm having some fun here