I'm working with Strummed Acoustic 2 and some of the patterns do not play when I scroll through.
I do have other VI's open as well (Omnisphere and Addictive Drums 2) Not sure if that's an issue or not.
I had the same problem in Luna so I exported the midi to Logic Pro 11.0 and have the same problem when scrolling through the patterns some play and some don't.
I thought the session was buggy so I put an instance on a unrelated Logic session with the same results.