> So it doesn't really matter what you intend it to say, as long as the grader can and does interpret something consistent from it.

Which, for any sufficiently complex and ambiguous sentence, any motivated reader will always be able to do.

I won't speculate on how large a percentage it is, but some percentage of these papers are straight up Rorschach ink blots, even if the authors themselves believed they were writing something coherent and intelligible.