I think you're exaggerating how bad it is.
There is no ambiguity in the rule you cited. In the absence of an erratum stating otherwise, I would simply apply it as it reads: it has no effect if you are at DefCon 4. Why? Thematically, it makes sense: when tensions are low, who is pushing for an NTB treaty? Such a treaty is meant as a way to reduce tensions.
It isn't that the rule isn't known in this case, it's that people are confusing what it says with what they want it to be.
There is no ambiguity in the rule you cited. In the absence of an erratum stating otherwise, I would simply apply it as it reads: it has no effect if you are at DefCon 4. Why? Thematically, it makes sense: when tensions are low, who is pushing for an NTB treaty? Such a treaty is meant as a way to reduce tensions.
It isn't that the rule isn't known in this case, it's that people are confusing what it says with what they want it to be.