Pattern Preview Oddity in P5 V2 Demo Tutorial

I've been having a blast playing with the P5 V2 demo, enjoying all the new toys - I'm definitely going to have to upgrade (at £50 it's really a no-brainer).

I've been using the tutorial file (File1.p5p) to play with the groove matrix & pattern editing (too lazy to create my own atm) and found a curious problem.

If I double click the "melody" pattern (Track 8), and try and preview it in the pattern editor I hear nothing. The synth on the track also seems to stop responding to MIDI notes - I hear nothing when playing my Oxygen 8, even if that little MIDI plug symbol is lit for the track.

However, if I play the song, the melody pattern plays - and once I've done this I can then play the "Melody" synth from my MIDI keyboard. This works fine until I try to preview the pattern again, and we're back to the pattern not sounding.

Can anyone else reproduce this? I'm trying to work out if I've found a small bug (*gasp*) in P5, problem with my setup or am I just suffering from a lack of understanding due to the lateness of the hour.

Thanks for any help

--
Ian