Just got this email from GS1. I see Amazon having issues with this so if you need to set up something new, using a GS1 barcode, do it now. I’m sure Amazon / GS1 will straighten out any glitches that develop because of this but it could take time.
Could be nothing based on the change but we all know how connected the pieces of duct tape are with GS1 / Amazon. I never like to take chances…
You’ve been warned - 
