IMG_20250309_144236 by Steve Weeks, on FlickrFrom looking at it, it seems to me (and my mechanic) that it's worn through over time. I spoke to the bloke i bought them from and he's not had a single issue (i believe him too).
So it's a bit of thinking about how/why.
Looking at the mech in terms of chain length/tension we're thinking that it's got a couple of links too many in the chain, which is causing some slap/flap at the top end.
IMG_20250310_081558 by Steve Weeks, on FlickrSo we've removed one of the links and when frame is at max compression this is where we're sitting.
IMG_20250310_085620 by Steve Weeks, on FlickrWhich looks like it's arguably still too many links by the time we wind out the B screw to get the mech to sit about right.
I'm going to drop into Rotec with it later this week so we can give it a full check, but i think it's 1 more link out to get it right. Weirdly though the chain is (i think) the same length as it came from the factory as every time i've swapped it i've done like-for-like in terms of length.. Although i may be mistaken and maybe somewhere along the lines i've fitted one that's too long.
edit. Now actually removed 2 links.



