Most PÄli grammars (Collins, Geiger, Duroiselle) produced in the west give the form of the possessive suffixes as -vant/-mant. But Narada's Intro, and Buddhadatta's dictionary follow the PÄli grammars in making the stem form -vantu/-mantu.
Since the 'u' plays no role in the declensions I'm interested to know why it is there, especially since western scholars silently dropped it in most cases (except for a very brief note in Warder's intro p.252, n.1).