Hello,

  As far as I'm aware, this isn't a known issue as stated. However, the fact that you have had two units exhibit the same behavior is a concern to me.

  What I'd like to do is create a support ticket for you and see what we can do for you in regards to warranty repair or replacements.

  I apologize for this as I know how frustrating it can be to have to deal with gear that is failing.

  Q: What is a support ticket?

  A: A support ticket allows you to directly correspond with a Line 6 Support Representative. An email will be sent to you from Line 6 containing a link if a Line 6 support representative determines that a ticket is necessary to troubleshoot your issue. Please follow the link in the email to view your open ticket to work one on one with Line 6 Support.

  Please note: Sometimes support tickets will be filtered to spam and junk folders. If you did not receive an email from us indicating that a ticket has been created, please make sure to check those folders in your email host.

  http://line6.com/account/tickets/view/

Edit: I missed the part where you said you returned it. If there is anything else we can do please let us know.

  Line6Miller