You didn't check "Case sensitive". It is mandatory, since you're looking for uppercase letters. Without checking this, then \p{Lu} (or [A-Z]) select any letter, not only uppercase.
Another mistake (mine, this time) : there was a mismatch in the history-box of the searches, and I put an old version of the string, it is not
Code:
((?:\p{Lu}\.)+)(?:(</(?:p|div|b/|blockquote)>)|( \p{Lu})|(' ')|(.))
but (as I put in my first msg):
Code:
((?:\p{Lu}\.){2,})(?:\s*(<(?:/p|/div|br/|/blockquote)>)|( \p{Lu})|(' ')|(.))
Both conditions gave this result. Terribly sorry for this !