Here's what the PMW says under the heading "The Office of the Keys", with a block of citations omitted to make it easier to see the problem:

God has given to His church on earth the Office of the Keys [citations here]. "The Office of the Keys is the special authority which Christ has given to His Church on earth ..."

This is not quite as important a point as the grammar problem I noted last time. It's a matter of tightening up the PMW so that it says what's needed as directly and clearly as possible. This particular problem comes from the department of redundancy department. Unless someone can explain to me the benefit of saying the same thing twice twice, I strongly suggest not doing so. I would recommend that the first sentence be omitted altogether. If any of its citations are too precious to omit, they can be placed after the quotation ends, as references to what's said in the quotation from the Catechism.

I hope that's clear enough. Hopefully, what I wrote is understandable.