That is when Fr. Pfeiffer was clearly rejecting the authority/leadership of a perfectly good Resistance bishop.
How is Bishop Williamson in any legitimate way, the authority or leader of Fr. Pfeiffer? He has no canonical authority and he has continually refused to be anybody's avowed leader, officially and/or unofficially. He is, at most, an independent Bishop who's issues with SSPX authority and direction mirrored those of Fr. Pfeiffer. They are not connected in any way except perhaps that Fr. Pfeiffer was formed and directly chosen for ordination by Bishop Williamson.
RED HERRING ALERT!
No one ever said Bp. Williamson has canonical authority over any Resistance priest.
The issue is that all over the world, virtually all Resistance priests acknowledge Bishop Williamson (and Bishop Faure) as good Resistant bishops, they are on good terms with both of them, etc.
There are really only two exceptions that I know of: Fr. Pfeiffer (and by extension, Fr. Hewko, though I think we all know that Fr. Hewko is just following Fr. Pfeiffer).
That is the problem. Why is Fr. Pfeiffer's tiny group the ONLY ONE that considers not only itself, but the whole Resistance to be "without a bishop"? Are there real issues with the Boston Seminary? Megalomania involved? Who knows. The specifics of the SSPX-MC's dysfunction are open for debate.
But what is NOT open for debate is that there is something very dysfunctional about Fr. Pfeiffer's operation. There are real, noticeable problem(s) there.
In summary:
1. Name one other Resistant priest (outside Boston KY) that considers itself/the Resistance to be bishop-less.
2. Name one other Resistant priest who attacks his fellow priests/bishops in the Resistance.
3. Name one other place (besides Boston, KY) where Bishop Williamson and/or Bishop Faure has refused to set foot.
With regards to #2, we've all seen ALL TOO MANY attacks coming from Fr. Pfeiffer, Pablo, Greg Taylor, etc. -- but notice they're all part of the same group.
When is the last time Fr. Morel, Fr. Zendejas, Fr. Ringrose, Fr. Girouard, or any other Resistant priest attacked someone in the Resistance?