Can you document this? Any photos? Really, I'd be interested. I have my opinions and I would like to see some proof of this assertion. And...if they were stretched, do you know what they were shooting to make them stretch?
It's been nearly 10 years since I worked for him, but I believe he kept a couple of the receivers that were bad. I'll do my best to see if there are any left that I could get pics of. IIRC, there were 3 or 4 with grossly excessive headspace (this I term "stretching". I know 2 went back to IO, who IIRC was the importer. I believe 1 at least was kept behind as I remember this being shown to someone.
As for what made them stretch? What else would do it? The Punjabs didn't use the receivers as comealongs to pull equipment with. But, they did use these rifles hard as cadet guns and were often shooting ammunition of nefarious origins or overloaded MG ammo.
I bought, and sent back, a 2A1 from CAI years ago that was hairline cracked near the knox form, and the bolt was sticky going into battery. What does that? Overpressure or bad metalurgy. Take your pic. Either way, it's not up for debate, the 2A action is not designed for .308 pressures and pushing it is damned foolish. Why even risk it? It's not like surp .308 is prohibitively expensive. You're talking about 10,000psi increases possible. That's nothing to take lightly.
I know far more about Brit Enfield production than later Ishapore workings (just try to find some good historical documentation of their production), but I know what I've seen and based on that, I would be hesitant to believe that the 2A/2A1 action is to be trusted with all grades of commercial .308.
I don't know of any catastrophic failures of the 2A, and that speaks well for the action but I'm still always going to air on the side of safety. There's simply no reason to mess around with a controlled explosion that's right beside your head, IMHO.