You do need to adjust your Reese Steadi-Flex Weight Distribution System # RP66560 on your 2018 Airstream International Serenity travel trailer. The metal grooves that you are getting at the hitch side of your bars tells me that there is to much pitch in the head to your trailer brackets. This could be caused by the hitch height of the ball being to high or the frame brackets on your trailer being to low.
I have linked the installation instructions below that will help you through the... view full answer...