This principle states what the Church of England corporately holds, not what individual members of it may or may not believe. But in any case, it is not problematic.
To understand it correctly, we must bear in mind the distinction between office and order. With parish clergy this is easy, because the names are different. ‘Rector’, ‘vicar’, ‘priest in charge’, ‘assistant curate’, etc are offices; ‘priest’ is an order of ministry. With bishops, however, we use the same word (‘bishop’) for the office and the order, and that may cause confusion.
If the Rector of Barchester is a woman, we don’t say that the office of rector is vacant. She is the true and lawful holder of that office. She is the rector, but we cannot say that she is a priest. There is in in fact much precedent for church offices that were originally held by clergy being held by people who are not priests: there have been lay rectors – and, in cathedrals, lay canons and lay vicars.
Similarly, if the Bishop of Barchester is female, she will be the true and lawful holder of the office of diocesan bishop. We cannot say that she is a bishop in the sacramental sense (order), but as ‘holder of the office of diocesan bishop’ she will be a bishop in the other sense (office).