TM KZ10b conrod size

I have an issue with renovating the bottom end of my KZ10b engine. It has from factory run a 22mm crank pin and conrod setup. But when i bought an fitted a new conrod assembly for the crank it touched the housing slightly. Then I measured the outside of the large end of the conrod and found out the the old one (still running 22mm pin and 22/28 bearing) is 39,5mm outside but the new one is 40,5mm.

I can most likely grind a tenth of a mm of in the housing and it will move freely, but I do not get why there are this difference between the conrods.

I contacted the dealer in Italy and the were confused and basically said that the 40,5mm is what it has always been if it is an original conrod. But the old one is also a an original TM conrod.

Have any of you encountered an issue like this.?