Just to be super clear about my own case, mine isn’t “know for a fact” – mine is in the category of “maybe”. My childhood denomination permits three formulas on paper, one of which is the now-declared-invalid form. This is why I’m seeking conditional baptism only – not absolute baptism. In my case it’s a matter of reasonable doubt, not absolute certainty.
In a case like this I can see a reasonable reason to ask for conditional baptism. I think the challenge is to do conditional baptisms of all clerical candidates or anyone baptized outside of the Catholic Church.
I get the idea of trying to make sure that everything possible is done to ensure the sequential nature of certain sacraments proceed as we understand them, but for a theological standpoint I think it has to go beyond just it might or might not have happened so we will just do conditional baptisms for everyone just to be sure. At some point we have to trust that the sacraments happened and deal with any issues when they occur.
The biggest issue I see is if we cannot assume the initial baptism is valid, then how can we assume that the conditional baptism was done correctly? We could see deacons with 3 conditional baptisms because maybe the conditional baptism at confirmation was invalid, and then the one before marriage was done improperly, but the one before ordination it stuck. It reminds me of part of Monty Python and the Holy Grail when a king is talking about the castle built in the swamp (1st walls sank, 2nd walls sank, 3rd burned, fell down and sank, but the 4th are strong).
I am not trying to dismiss your concerns. In my diocese there have been tons of discussion around the issue and how to balance trust that it was done right versus being overly cautious.
Personally I wish the CDF had said the words must be said by the same person as pours, but had allowed greater leeway around I vs We. I get what the issue is around intent, but it’s getting to the point that people are starting to question any baptism that they did not personally oversee. It’s not healthy for the church and just becomes a distraction that doesn’t seem to have ever came up in 2000 years previously.