AI is a bane of formatting. When Libre Office sees my name, M. Douglas McIlroy, at the beginning of a line, it renders it by default as a paragraph numbered with Roman numeral 1000 (and labels the next paragraph MI). While groff is not so wild, it does have AI foibles in intersentence spacing and in intersymbol spacing in eqn.
To my eye, two spaces between sentences is excessive. So I often set the sentence space to zero. The output looks fine; and AI never bites. Doug