[dcl.contract.func]/4 Missing IFNDR

The issue points to missing IFNDR (ill-formed, no diagnostic required) clauses in the C++ standard draft. Start by reading the linked sections [dcl.contract.func]/4 and /5 and the IFNDR annex G.6.4. Compare the wording to identify the discrepancy: one IFNDR case about mismatched contract specifiers in first declarations across translation units is documented, but another about non-first declarations may be missing. Verify the draft's structure and propose an edit to the LaTeX source, likely in the relevant .tex files under the 'dcl' or 'ifndr' sections.

[dcl.contract.func]/4 says

A declaration D of a function or function template f that is not a first declaration shall have either no function-contract-specifier-seq or the same function-contract-specifier-seq (see below) as any first declaration F reachable from D.
If D and F are in different translation units, a diagnostic is required only if D is attached to a named module.
If a declaration F₁ is a first declaration of f in one translation unit and a declaration F₂ is a first declaration of f in another translation unit, F₁ and F₂ shall specify the same function-contract-specifier-seq, no diagnostic required ([ifndr:dcl.contract.func.mismatched.contract.specifiers]).

There are two IFNDR cases, one about not-the-first declarations and another is about first declarations.

However, G.6.4 is only about the latter case.

If two different first declarations of a function (which must therefore not be reachable from one another) do not have equivalent function contract specifiers the program is ill-formed, no diagnostic required.

BTW, [dcl.contract.func]/5 has a totally missing IFNDR

... If this condition is not met solely due to the comparison of two lambda-expressions that are contained within P₁ and P₂, no diagnostic is required.