ABL was not just concerned with intention, but with the validity of orders.
In any event, sacramental theology teaches that when a Catholic minister brings together the matter and form for a sacrament, it is presumed (i.e., we have moral certainty) that he has the proper intention. After all, it just makes sense.
But what TKGS is driving at, is that a common argument against sedevacantism is to say that the post-conciliar popes heresies cannot be said to be formal because we cannot know that they intended to express heresy when they do. Narrowing down on this very particular argument, there is a conflict between believing we cannot know the intention behind manifest heresy, but we CAN know the intention behind a manifest declaration of canonization.
You have abandoned this argument from intention, so there is no necessary burden for you to answer the question, but it is a very poignant one for anyone who takes that position and simultaneously argues the VII popes can't be called formal heretics because we don't know the intention behind their heresy (there are other problems with this argument, but just focusing on this one obvious conflict).