Hello,
This message is just for bug report.
from wiki, the below example should switch back page 4 in portrait mode, but it doesn't. (ConTeXt ver: 2014.11.17 14:32 MKIV beta)
\definepapersize[main] [A4]
\definepapersize[extra][A4,landscape]
\setuppapersize[main]
\starttext
Page 1. Portrait \page
Page 2. Portrait \page
\adaptpapersize[extra]
Page 3. Landscape \page
Page 4. Portrait \page
\stoptext