I can’t reproduce the problem, the text on the second page stays on the grid.

Wolfgang

Sorry, my fault, wrong number in \dorecurse.
Now you can reporduce it, I think.

\setuplayout[grid=yes]
\showgrid
\setuphead[subsection]
[after=\vskip-1.6mm,
before={\testpage[5]\vskip1.6mm}]]

\starttext
\dorecurse{18}{Linefill\\}
\input tufte
\subsection{Hallo}
\input tufte
\subsection{Hallo}
\input tufte \input tufte
\stoptext

Huseyin