Over cab bed area external crack, Should I be concerned?

If you were really concerned and didn't mind looking a little bit redneck-there-I-fixed-it you could route two straps from the front of the overhang across the top of the overhang and down the roof to the back of the camper.

I probably should have done this when building our camper as I could have put the straps underneath the aluminum roof coil to hide them. I did put a GoPro under the cab to see if it was flexing or bouncing and saw no movement so perhaps am ok.