I'm convinced this is the sole reason why you also always see those large "nickel to quarter" sized chips on the sides of the bowls. If you look where those chips are...they are almost always right over the spot welds for the bowl brackets that hold the charcoal grates up.
I've never banked my coals against the side of the bowl and have NEVER gotten a chip in that area of any of my grills.
I do believe you're at least 95% correct......
Couple of instances come to mind.......
"Bob", my main smoker, had two very small chips at those points when I got him; he's only done two high heat performances.........
One, a burnout to then do vegan 'turds ( a sort of 'challenge' from somebody on Smoke Ring ) & a hot fire in the seasoning of the big original style wok......other than that it's all 300 degrees & lower.......
Chips remain the same......
I think the problem occurs when people want to do 6~700 degree pizzas & seared steaks & such, with banked coals & no basket; it's just too much for the slight weak point, the Achilles Heel, of the kettle......
The other thing I remembered is being present when a kettle was "shocked"
A guy went to move the thing quickly & the wheels went out from under it......slammed on the concrete, golf ball sized chips at the handle attachment points where it hit, lid flew & landed on the handle, chips at both points there......
Also later noticed chips at the upper & lower grate holder weld points ( like you say) from the shock......heat is usually the cause...............