Sticking exhaust flaps on brand new unistalled cylinder, 2003 cr125.

Got a brand new stock cylinder and replaced everything apart from the exhaust flaps and shaft, the exhaust flaps were out of a 56mm cylinder so have had 1mm taken off them,

They run smooth in the 56mm cylinder, but in the new stock cylinder they don't fully shut, as in the powervalve shaft stopper never fully sits on the cylinder stop pin, there's a little gap, and it binds up when the exhaust flaps are fully open or fully shut when operating the powervalve shaft by hand.

It's obviously the flaps touching the cylinder, but it seems counter intuitive as i've taken material off the exhaust flaps giving more clearance... i'm assuming the extra clearance is causing them to pinch ?

Would this be the case, as the brand new honda cylinder does look rough AF, it has loads of casting marks, and it also looks like it may have slipped in the jig as it has a few weird scuff marks up the side, and the clean up work around the where the exhaust flaps fit is shocking, it looks Chinese, not Japanese, but it's oem honda from a honda dealer...

Lastly, it has "ET" etched/stamped on the flat side next to the powervalve cover, i've had a new one before and it never had this marked on it, neither did the two used ones i had, what's it mean ?

Bikes a 2003 cr125 if it makes a difference,

Thanks in advance.