Hello list,
sometimes ConTeXt moves the (would-be) last line of a page to the next
page, even when there's room for it at the bottom of a page, before the
footnotes.

Sometimes i understand why it does so: when the line contains a footnote
that would increase the footnotes' height, for example; or when you have
widows or orphans.

But sometimes it happens in an inexplicable way: in some pages there's
room at the bottom and it keeps the last line, in some other pages
there's more room (than in the previous case), but it moves the last
line to the next page anyway.
Even looking at hyphenations, i can't find an explanation fot that
behaviour.