The following code (using latest minimals)

\starttext
\startitemize[n]
\item FOO
\startitemize[a]
\item Hello
\item Good bye
\stopitemize
\stopitemize

\startitemize[n]
\item
\startitemize[a]
\item Hello
\item Good bye
\stopitemize
\stopitemize
\stoptext

gives the attached pdf file, i.e. the second nested list is cut. Has
something changed (I've been able to use nested lists before without
having to use FOO or something inbetwen (as in the first example)? I
tried to reinstall, but the same problem appeared again.

Best regards, Mikael