Hi Martin.
I took Bruce (the scram) in for his service this morning so I've had a good look at 4 guerrillas in the showroom plus the demo bike they lent me. I also had a quick glance at mine to make sure it's OK and it is.
The 5 machines at the dealers were all fine and the sales guy said he's not heard of a problem with the shock. He also reckoned the dealer should get a replacement within days.
I've looked more closely at the tang ring to figure out how they probably make them and why yours might have gone wrong. First off the ring is actually a ring and not two separate pieces as I'd assumed from your photo. It's clearly split as can be seen on your photo, but it's a complete circle otherwise. Then it twigged how they most likely make it. It looks like a pressed piece so I reckon it's pressed in the flat then rolled into a circle, not quite meeting at the join. In fact a close look on these bikes you can see the circle is slightly misaligned by about 0.75mm. The welds on these bikes and mine seem longer than yours. I'd say each stitch is about 10mm long.
A very close look shows where the problem might lie. The fit of the ring onto the shock body isn't that close, so there's a gap to the shock body, plus the gap gets slightly bigger as you get towards the end of the tang. It's not much and you need to look closely to see it. But if there's a lot of friction between the tang and cam ring I could imagine it would tend to splay open the gap. Especially as the edges of the tang aren't perfect, with it being a pressed piece. Maybe then the forces applied through the suspension would finish the job, splaying it out more. I think that's possibly what's happened to yours.
I bet most people don't adjust them. I haven't needed to and probably never will unless the missus wants a run out on it. I think it'd be wise, with hindsight, to lubricate the two parts prior to twisting it.
That's my best guess, now having seen the thing up close and not via a photo.
Hope these ramblings make sense and maybe they're of some help.🤷
Cheers