Assuming you have a PO420 code there are lots of things to check that can set that code. The good news is that it likely won't cause you any drivability issues and you can probably fix it when your trip is finished. https://www.way.com/blog/p0420-code-...exhaust%20pipe.
2011 Winnebago Via 25Q on 2010 Sprinter Chassis
If I had to guess, it is from ethanol in the fuel. Try to get low or zero ethanol fuel and see if that fixes it. Your Godzilla motor is very new, and the only thing we have been seeing in some of them is spark plug wires that get too hot and fail.
Welcome to the forum.
2019 Minnie Winnie 22M on an E-450 frame