Gudgeon Pins / Strange Wear Pattern

[ChequeredFlagRacing]

Cranks rebuilt by Grampian supplied with small end bearings
Pistons from Yambits who get them from Grampian
video https://www.youtube.com/shorts/tW7JJgv_43I

So first start and it sounded like a four stroke with a timing belt out by a tooth

Took it apart to inspect and couldn't see anything but didn't look at the gudgeon pins as the noise appeared to be ring based at TDC / BDC and all looked new. Went back to Mick Abbey for him to check his re-bores and all was fine. 

Rebuilt without any changes just worked through checking and double checking as I went

Second start and still the same!!!
So pulled it apart and when I took the rings off the noise went away. 
So new piston kits loaned by Mick Abbey who did the rebores. His rings on my pistons and the noise was the same. So decided to swap to his pistons and that's when the wear was found on the gudgeon pins.
I'm talking with Yambits / Grampian to try and find a reason this is happening as I'm stumped

[Luther]

All 4 look like that?? Well the pin should slip around in a warm piston. That should keep it from showing uneven wear. It looks like the bearing cage is dragging at the ends and my bet is distorted or just badly made cage

Luke

[ChequeredFlagRacing]

All 4 look like that?? Well the pin should slip around in a warm piston. That should keep it from showing uneven wear. It looks like the bearing cage is dragging at the ends and my bet is distorted or just badly made cage

Luke

Yes, all four are the same