Just had a great chat with Landon at Deep6.
We talked about the new thrust washer. It's very thin, and provides that extra bit of anti-friction if you're spinning the faceplate on quickly.
I'm assuming that's how that one old Signature second arrived from the factory with that fold.
But as I've noted in the problem-free years since, if you close the faceplate slowly, the reg is designed (for cavers) to not require a thrust washer. I've certainly never had the issue arise again.
And I'm honor-bound to say mea culpa, regarding that broken exhaust cover tab in a post I made upthread: when I looked for the problem reg among my multiple Signatures, I couldn't find a broken one. But my HOG, (with a similar exhaust cover molding) DID have the crack I'd remembered. The plastic in the HOG is less durable, while the fiberglass impregnated plastic in the Deep6 case is stronger, and didn't break. I apologize for blaming the wrong guys. When Chris left HOG/Edge to form Deep6, he brought his good ideas with him.
All this talk about Apeks and HOG clones is generalizing off superficial similarities in cylindrical shape. Anyone who has disassembled the balance chamber of a Signature 1st next to a HOG D1 would never say that. I like my Signatures, and for the record, the environmental seal stays sealed much better than my new and expensive SP Mk19EVO. The IP spread from full to empty tank is better than Scubapro's, too. And that's despite the improvement in the Mk19EVO's IP stability over the Mk17. Deep6 Signature still beats it.