Since you are a professional do you think the pull top somehow let air in when it was dented? The top appeared & felt like it was sealed but I didn't study it before opening.
I dont think we have ever done any tests with regards to that, ie the durability of the score after being filled, cooked, packaged because that's all done down the street at Nestle Purina. The tests we do for the score are the 1st pull, which is when you pull the tab up to pierce the score, second pull weight is how easily the lid comes off after that. Along with a whole host of other tests that I wont go into. The cans themselves are ran through a light detector that can detect light through a hole as small as .002". They are checked for height, the flange width (which is what the lid will seal onto later), attribute defects (dents, burrs on the flange, hairing of the metal, slivers, grease, etc). If you peel the label off you might see some printing on the can....its Video Jet ink which tells when the can was made, julian date, time, what plant, which trimmer....the ink is normally black but turns pink/blue when its cooked.....that's how they can tell by glance if its actually been through an oven.
Where the lid meets the flange, compound is sprayed into the valley to help insure a seal. We've done crude tests before and determined it doesn't matter how little or how much we spray compound in there....it will seal with no compound, and it will seal with 3X the normal amount and none will squeeze out.
I'm not saying it isn't possible to dent a lid bad enough to break the score, but it would have to happen after it was filled, sealed, then cooked...otherwise if the lid isn't sealed they tend to blow up in the oven and make one helluva mess.
Time to go to work....I'll be running the press that makes that can tonight.
Edit: these are SOME of the tests we do locally. We do have a test/engineering plant that looks into specific issues, improvements etc. I'll do some checking tonight on what it would take to break a score without piercing it. I know it takes an rather large amount to get the can to buckle.