A priest in a parish baptized two children using the proper rite for baptism, pouring water properly, but saying "WE baptize you in the name of the Father and of the Son and of the Holy Spirit".
The proper form for baptism in the Latin Church is "I baptize you in the name of the Father and of the Son and of the Holy Spirit… Ego te baptizo….".
It seems there was nothing wrong with the rite, or the intention of the minister, or the matter, but the form left a big question mark.
The questioner asked: "Was that valid?"
First and foremost priests should stick to the form as it is so that people don’t have to wonder or be puzzled.
That said, my first inclination was that it might be invalid.
I have rethought my position.
First, there is a possible use of the plural first person for the singular, the so-called "royal we".
Second, the core of this form is the invocation of the Holy Trinity. And not just any Trinity. The Mormons invoke their own "Trinity" and their baptism is invalid. Some progressivists and heretics in the Church use titles other than the Father, Son and Holy Spirit, such as "Creator, Redeemer and Sanctifier". That is also invalid.
That is not what happened here. Also, the priest used the rest of the Rite properly.
Furthermore, in the Greek East the form of baptism is (transliterated): "Baptizestai ho dolous tou theo (ho deina) eis to onoma tou patros kai tou huiou kai tou hagiou pneumatos… The servant of God is baptized in the name of the Father and of the Son and of the Holy Spirit." This is a declaration, in the third person passive, rather than the acting of the minister speaking in the first person. Again, the invocation of the Holy Trinity is a key, together with the expression of the effect, the sacrament. If the third person passive can be used, why not the first person plural?
Moreover, in the so-called Decree for the Armenians in the Bull Exsultate Deo of Eugene IV in 1439 we have this famous teaching: "Se exprimitur actus, qui per ipsum exercetur ministrum, cum Sanctae Trinitatis invocatione, perficitur sacramentum… If the act which is exercised through the minister is expressed with the invocation of the Holy Trinity, then the sacrament is effected." (Cf. DS 696).
So… I think what that priest did, even in changing the form illicitly, was probably valid.
If anyone who hears something like is concerned enough to want to raise questions, he should approach the local bishop right away. If no clear answer is obtained, then the proper dicastery of the Holy See to write to for a clarification would be the Congregation for the Doctrine of the Faith, send exact details about what was said and done in that instance leaving aside speculations or rambling irrelevancies.
The CDF answers questions about specific, concrete instances of celebrations of the sacraments while the CDW would respond to the more generic or theoretical questions.