I purchased a JTV 69 a couple of years ago to be the one guitar needed for a gig. Mostly terrific and I had it professionally set up and use 09 string sets, I developed a problem where when I am using the les paul standard setting, on occasion, the guitar just drops a half step. Most noticible here and in the middle of a gig, it sucks. I then hit the modeling off button and it usually resets or the same when I remove the battery and then put it back. The upper tunings button usually begins to flash and I get a strange warbling tone when it does this.
I had it in a local authorized shop who failed to fix it and then sent to line 6 in california last year where they had it working.until recently. Not sure what gives but guitar plays great unitl this