As a full timer you have the ability to call Keystone, explain that you are very concerned and just are not happy with the dealer fixes, ask if you can bring it to Goshen for them to look at. Yep, on your dime. But, if you have not been to Goshen, you MUST! So much to see and learn about rigs there, plus Elkhart County is beautiful, and there is Amish cooking and MORE!
Ask very nicely, don't ask for them to fix first off, just ask for them to look at it.
Guessing, this is the ole frame flex.
It would be helpful to us if you add your year and make into a signature line.
In the meantime, enjoy the unit,
Cheers.