Given that the person in question appears to be an adult, I assumed that this was not the case (since as you note this is a recent development–and I know of at least one case where it happened in your own Communion and the bishop had to find the people this priest had baptized and rebaptize them, so it’s not just an Episcopalian problem).
It’s a problem in every ecclesial organization these days - no one has a monopoly on well-meaning stupidity.
However, in the past your Communion took a stricter view of our baptisms and those of other separated Western churches. Our baptisms were not seen as absolutely invalid, but as being highly dubious.
In the book I have that is a guide to priests on how to deal with converts to the Catholic faith (printed in 1957) it tells the priest to instruct the candidate not to try to track down his record of baptism, so as not to alert the other church that he is converting to the Catholic faith. The reason isn’t given - we could speculate all day, I suppose, but I think we both know that there wasn’t a whole lot of communication between Protestants and Catholics in those days, and such as there was, was not exactly amicable, on either side. So they solved the problem by simply giving
everyone Conditional Baptisms and First Confessions, regardless of their background.
When I was leading RCIA, I had moments when I thought that a system like that would certainly simplify things - quite often, people delayed tracking down their baptismal information until the week before the Easter Vigil when they suddenly realized that it makes a difference, which Rite they will be going through, whether they have the information or not (it usually takes about three months to receive the documents from the original church, assuming the person even remembers which church it was where he was baptized, that the original church hasn’t been burned down or blown away in some natural disaster in the meantime, that they are the sort of church that keeps these kinds of records to begin with, that the records didn’t get lost or mislaid during the period of time when they were training their new secretary, and that the secretary is actually willing to hunt through the archives and find it for you, even if she knows for sure that she has it.)
There were a lot of tears and panicking when people didn’t have their baptismal records turned in on time, and I always used to think that the old way of doing things would certainly have saved a lot of stress and aggravation, even though it’s really not proper.
G. K. Chesterton was baptized, I know (and wrote a great poem about it–if anything could justify rebaptism, that poem could!), and so were most converts from Anglicanism in the 19th and early 20th centuries as far as I’m aware. These may have been conditional baptisms, although some of the accounts I’ve read don’t say that and leave one to assume that they were just plain old baptisms (perhaps one was expected to know that the conditional formula would have been used–I’m not sure).
Well, they were using the conditional formula in 1957, and it seems reasonable to think that they were using it in the early part of the 20th century, as well.