IMO what happens to the Cat chain cases that blow that are not a result of impact damage:
They are made of magnesium. Magnesium has a much higher rate of thermal expansion than aluminum. Magnesium expansion coefficients vary widely depending on the alloy, but lets say you pick one in the middle of the range. I haven't measured how far apart the jack shaft and track shaft are C-C in the sleds, but for argument sake assume 18". Put that together and that 18" distance increases by up to 1/16" unrestrained with a temperature swing of 100-150 degrees F (can't remember what I used years ago when I calc'ed this). That means there would have to be enough slack in the chain for it to increase it's length by 1/8" (1/16" up and back down). So imagine it's 0 degrees on a cold morning, the chain has worn into that aluminum lower sprocket a little, and that auto tensioner gets one more click tighter that it was on the edge about before. Now fire the sled up and start riding, deep snow starts covering over the hood vents, underhood temps rise, chaincase starts expanding, aluminum lower gear starts expanding, and you hit the other side of a creek crossing with the track under full load with a fiddle-string tight chain...
Now the numbers are probably a little different here and there, but that's the concept. This also demonstrates why you have to leave a belt drive belt loose, and it gets tighter after everything heats up. Cat's fix after 2015 was to put a stronger chain in that doesn't break as easy. It seems to work, but doesn't really address the root problem.