[HarleyD]

A better example would be the apostolic succession of the Anglican Church, which was valid for a while.

How on earth can "apostolic succession" be valid "for a while"? Either you can trace yourselves to the apostles or you can't. Validity, in my mind would not enter into the issue.

[annalex]

I defer to the posts of others that corrected me; this however, I can answer: apostolic succession requires two things: valid consecration and unity of doctrine. It is possible to consecrate a bishop or even a succession of bishops who drift into heresy overtime. At that point firther consecrations cease to be valid.

[redgolum]

I suspect it has something to do with the English Civil War, and the expulsion of the Anglican bishops after Cromwell’s Puritians won. At least I have seen it expressed that way once.