Hmmm.Its not so hard to believe when you consider the differences in something else I'm learning about-the specs of SAAMI,CIP,and NATO 9x19 Parabellum.
Some countries load their ammo hotter than others,for sure.
But I still dont really think thats what is causing your problems.
You could always get some Yugo surplus ammo and try tho.....
A decent pistol chambered in 9 para should be able to shoot the weaker SAAMI stuff along with the hotter stuff.
You just dont want to use the hot stuff in an older pistol,so I am told and which makes very good sense to me.