Had the same thing happen to the ’96 Romeo engine in my Cougar, before I bought it. It turned out that the previous owner let it run low on oil and it squeaked the cam in the passenger side head.....also broke a few of the rocker arms (feelers) and bent the head of one of the valves when it went crashing into the piston.
When I rebuilt it, I installed a Cobra High Volume pump to insure that there was never a shortage of oil to that area again. I swapped out a set of PI heads and cams to the short block, which I received unassembled. I had to mix and match the retaining caps around, as well as polish the cam and head journals a little with some fine emery cloth, then work the cam in a little with the electric drill and assembly lube until I was completely satisfied with the way it was operating. You can't just slap these suckers in. You've got to torque them properly; otherwise they'll get tight on ya.
It may have been a case of neglect on their part, or it very well may have been a case of you letting it run a little low on oil during break in. So, you may want to make sure this wasn't something you did, before you go pointing any fingers.