Thanks — I think this is a good distinction.
CP-T05 can still be satisfied here: the invalid/error state remains explicit and nothing is silently turned into a PASS.
The problem is one layer later. If the fill value and aggregation rule can improve the resulting score, then a fully disclosed transformation can still strengthen the aggregate claim.
My reading is that this falls mainly under R-CP-4 together with R-CP-6: the numerical transformation, metric direction, aggregation rule, and population semantics all matter. Calling a value a “penalty” does not by itself establish that it is non-improving over the metric’s actual domain.
So I would not treat this as a CP-T05 failure. It looks more like a useful counterexample for testing whether R-CP-4/R-CP-6 are strong enough in practice.
Thanks for raising it — this is exactly the kind of edge case I was hoping people would test against the draft.