Immediately UE emerged, I went via a link on Fr Zed's blog to the Latin text and printed it off. As one does, I instantly noticed that the last sentence of paragraph 15 in the Latin text is missing in the English version. It occurred to me today to see whether the other translations omit it ... so I went to the Vatican website and discovered that they did. While I was there, I had another look at the Latin version ... and discovered that the sentence in question was missing there!!!
Here is my hypothesis. Fr Zed provided a link on his blog to a copy of UE which, in breach of the embargo, had been sent to him a little while before. In the interval between Fr Zed getting that version from his leaky chum, and the official publication, a last-minute change was made in the text.
[QUAERITUR (as Fr Zed so neatly says): was that change made after or before the Holy Father saw and approved the text on April 8?]
The sentence concerned: Ad numerum fidelium huius coetus designandum, pastoralis succurrit ratio, cautis tamen circumstantiis aequa lance ponderandis. Is all this evidence that, right up to the last moment, there was still nervousness about the question of how many people it takes to make up a coetus?