I have not actually come across this yet, though it has been close at times. If this were found then I would expect that some careful retermination of connections would resolve the problem, you are talking a fraction of an ohm here.
Unfortunately with circuit breakers if the resistance level were exceeded then the disconnection time could jump from practically instantaneous up to 13s (if the circumstances were just right, the type B CB is on the upper limit of design(5In) and the supply voltage is down to 218V) this tends to mean that non compliance could be significantly dangerous, though as you say it was deemed safe three years ago, only the definition of dangerous has changed.
If it were a fuse then a faction of an ohm increase would not significantly increase the danger as the time would be 0.401s instead of 0.4s and this might be suitable to be coded as improvement recommended. I think (silly as it sounds) if it is a circuit breaker then a potentially dangerous situation by the new definition of dangerous is now in place.