That side bunk is a pretty good lever trying to crank the TT side-to-side. And if your stab jacks are same as mine I'm not surprised that you get a rocking.
2013 F-350 CC SB 2WD 6.7PS
2013 Eagle Premier 351 RLTS
-SOLD- 2012 X23B
-SOLD- 2003 Ford Expedition 5.4, Bilstein shocks