[NTG-context] Overwriting buffer causes LuaTeX error

Hi, the following example causes 1) strange message: “invalid \starttext ... \stoptext structure” and 2) !LuaTeX error: PDF inclusion: file has changed 'Hga-typeset-buffer-001.pdf' ==> Fatal error occurred, no output PDF file produced! \starttext \startbuffer [foo] foo \stopbuffer \typesetbuffer [foo] \startbuffer [foo] foo \stopbuffer \typesetbuffer [foo] \stoptext Marco