It's interesting noting the report does not give a cause for the piston failure.
Looking at the cylinder scouring, that piston was definitely picking up before the failure.
I'm also wondering what caused the half moon shaped indent in the combustion chamber ?? Given it hasn't dropped a valve, very symmetrical and to small a radius to be the edge of the piston skirt, it can't be seen in the photos if the gudgeon broke up ,or the conrod.
While the die grinding on the piston is hardly neat ,would it cause a stress fracture ,given the very sharp radius on the inside of the piston skirt would be a much more susceptible spot for a crack to start. ( which they all have )
If piston to cylinder clearance was the cause you would imagine failure would have occurred much sooner in hours after the rebuild ??
While it sounds bad that a non genuine piston was used and I can't comment on a time frame outside of 2000-2005, the pistons were a well known brand of automotive piston at that stage.