As Pole I never had this issue. Why would you even use US Intl keyboard. Even for Arch with install everything manually I haven't any issues
Because (for some reason) you don't have your "standard" keyboard - just the US ISO one
Some keyboards have an extra key (or maybe more than one) and hence can't be mapped fully with a US keyboard
Coming from Windows this is very common
In Poland we informally use combinations and maybe some Poles use letter per key but I my entire live I never met a single person to do so