Some of the links on this forum allow SMF, at no cost to you, to earn a small commission when you click through and make a purchase. Let me know if you have any questions about this.
I don't have that smoker, but is the warpage hindering performance and functionality? If not, I wouldn't worry too much... sheet metal is gonna warp with heat.
If it's messin' ya up, try a 1" wide 1/8" thick chunk of aluminum stock screwed in diagonally across the pan. That should pull 'er back. Put a bead of Hi Temp siicone underneath it to prevent leaks.