I have never had this happen before, but I just bought a new VisionDaw PC and it is running Kontakt 2.2.
I also have another VisionDaw PC running Kontakt 2.1.
Both have RME 96/52 Sound/Midicards
Both are being triggered remotely through Pro Tools on a Dual 1.25 Mac through a MOTU MidiTimePiece AV.
On the new PC only, I am getting every minute or so, random singular note events happening out of nowhere, even when the computer is at rest. It is very annoying. It never happens on the older PC or on the Mac.