Ok, well that's nice but nothing you have said has offered any assistance or shed any further light on the issue. There is clearly something wrong with some of these guitars and it is not good enough for users to keep sending them away for servicing only to have them come back with the problem persisting and telling the user that there is nothing wrong with it. Clearly that is going nowhere and achieving nothing, wasting people's time and pissing people off.
Do Line6 take this issue seriously or not? If they do then why have they not figured out definitively what is actually happening to cause this?
The thread that I linked to was started in 2014 and has continued up until the present for the fact that that the problem hasn't been resolved or even properly acknowledged.
Some people are having to put felt under the string to try to stop the gnarly overtone and some are experimenting with gluing down their piezos with limited or inconsistent results. If people are having to experiment as such just to get the guitar to work as intended then clearly there is something fundamentally wrong with the product.
I appreciate you are on limited time due to the nature of your work but this issue requires further attention as it has not been rectified.
I suggest you look over the thread again and try and pick up where you left off because it does seem as if this issue has been abandoned. Thank you, Ant.