Sorry, I can't parse the sentence "All but the last two crossreference the parent subclause [expr.prop], with two sibling subclauses in-between." Could you try again, please?

I'm using crossreference as a verb here. The list of references in the parentheses are uses of the term "unevaluated operand". They are supposed to crossreference [expr.context]. The last two in the list do, but not the rest, which instead crossreference the parent subclause. Those that crossreference the parent subclause of [expr.context], which is a .3 leaf subclause, have an error of two (lengthy) subclauses from the actual reference to the intended reference.

Thanks.

So, in order to improve the general situation, we need a \label{term.unevaluated.operand} at the point where we define it, and then we can just \iref{term.unevaluated.operand} where we want to refer to the section number.