Presonus - random double midi notes

[jjones]

I have problem where when I press a key on my midi-controller I get a double attack once and a while, roughly every 5 notes with no relation to velocity. I'm using Presonus interfaces, Firepod and Firebox. Both have the same problem and are otherwise working perfectly. I've tried different controllers, different audio programs. It's most notable when using piano sounds, like in Logic or Akoustik Piano. I'm using iDeneb 10.5.5. Just for kicks I tried the AppleFWAudio for 10.5.6 with no change.

 

EDIT: I only have one midi cable connecting my controller to the interface so it's not a 'thru' problem.

 

Has anybody seen this before? I'd be very grateful for advice as this is PITA.