I wonder what this tag looks like the end of the URLs in AMP in Google Analytics. Can you configure or remove it?
This is being added randomly to Google Analytics itself. We do not have any control on that. Many users have reported this but we don’t have any idea why are they adding this.
I don’t think there is anything to be worried about this. You can ignore this one. As soon as I have some update on this, I will update this answer.