It is my understanding that \abovedisplayskip and \belowdisplayskip should adjust how much (rubber) spacing that is allowed between display math formulas. I have attached a ConTeXt file (bug.tex) that seems to indicate that setting these skips does not affect this (rubber) spacing. I have also translated this ConTeXt file line-by-line to a LaTeX file (bug.ltx) and attached it.
Both files produce a PDF (using `context bug.tex` and `pdflatex bug.ltx`) in which the spacing between the formula changes from page 1 to page 2 simply by adding the final formula. However, by changing \adjustdisplay{0} to \adjustdisplay{1}, the LaTeX file produces a 3 page document where the spacing between formula does not change (as expected) on the first two pages and thus requires a third page to typeset the final formula. However, making this same adjustment in the ConTeXt file does not seem to affect the output.
I would appreciate any thoughts as to why this is happening, and I would equally appreciate a solution to keeping the spacing the same in the ConTeXt file and thus bumping that last formula to a third page.
Troy Henderson