Fr Edward McNamara has been asked about the validity of a baptism conferred by a deacon, who for the sake of "everyone being involved", normally got someone else to pour the water, rightly Father says it is likely to be invalid.
It makes no sense whatsoever to say, "I baptize you" if in fact someone else is doing the baptism. ("Baptism" means to bathe or dip.)
It is not a practice I have heard of in the UK but it is as Father says:
Sadly, this is not the first time that the above erroneous practice has occurred. In another country the Holy See ordered that several years of baptisms be repeated, or, rather, carried out for the first time.
It is what happens when we invent liturgy. Salvation is doubtful.
Just to throw a small cat amongst a flock of pigeons, isn't what is described what happens at a British "royal" baptisms in the C of E. By perrogative one bishop holds the child, another pours the water, a third pronounces the formula.
Is it a practice that exists elsewhere in the Anglican Communion where there are several clergy in attendance?