Well, yes, but that's because what's inside the parens is an operand of an operator whose result is an argument to the function. It's not any different from:

some_sub(EXPR1 + EXPR2)
[download]

EXPR1 is evaluated before some_sub is called. And since perl5 doesn't have lazy evaluation, and unlike to get it any time soon, it's going to stay like this for a while.

But that has little to do with precedence (or at least not with the precedence people talk about when talking about operator precedence); the only 'rule' that's in effect is that arguments (and parameters) are evaluated before the operators/subs themselves.