How to prevent a midi patch change from going to my keyboard?

I have a casio privia hooked up through a USB port. I recorded some midi. When I play back the midi, a patch change is sent to the privia of some sort. On the midi track, channel is set to "none," patch is set to "none,", and bank is set to ----. There is no patch change in the event list. It appears to be somehow resetting the patch that I already have on the Privia, so that it is playing the same thing in two layers (causing phasing/comb filtering type of sounds). This "phasing" effect shows up on all patches, as if something were being doubled, so maybe it isn't quite a patch change. Mystery to me. So far, I have only been able to kill it be turning the piano off and on. Any hints? Thanks.

local echo off on the board?

  Local echo.....can't find it in the PDF manual. Do you guys have any idea what else the manual might call it?

  I think you guys were right.... I googled it, found something called "local control." Shut it off, so that the keyboard is not making any sounds, and sure enough, the midi playback does not cause the wierd sound problem. Not sure I quite understand what is going on, and a bit of a nuisance, as I have to turn local control on to record and off to playback, but it works.

http://www.cakewalk.com/D...p;Req=Playback.34.html

Problem solved after some detective work: The casio was responding to the keyboard twice simultaneously; once from local control and once in a loop through the keyboard track in sonar.  Therefore it was playing the same patch twice, layering, but not perfectly in phase.  If I shut off "local control" on the keyboard OR "echo keyboard" from sonar the problem would go away.  I would imagine that this might be an issue with other brands of keyboards, maybe.  Perhaps someone could try it out.