Maybe so, but I've never seen this before even in completely seized top ends. As mentioned, there was no evidence of a severe heat condition, just debris ingestion. Even the rings were still free. That said, and keeping in mind this is a strato saw, I can see fines collecting and baking to the underside of the piston crown when injected through the strato port but not making it all the way through the exhaust cycle (even though that would happen toward the end of it) -- unlike being sucked straight through the intake and blown out muffler after combustion.
All I do know is an OEM top end for a MS362 is $235 and I'm only speculating on the cause of how the original one got damaged, though I am inclined to stick with the loose air filter theory considering I can't find any other reasonable explanation. Just makes me nervous putting it back together without absolutely knowing what happened.
Don't get me wrong. I'm grateful for the input. Just hoping for something more conclusive before I commit to putting a new top end on it.
Otherwise, Hooray Hot Rod 039! LOL That thing is gonna rip.