Or am I doing something wrong?

With the following, Schwarzenegger is not hyphenated according to the instruction. I get:

\mainlanguage[en]
\hyphenation{Schwarz-en-egger}
\startexceptions[en]
epi-graphs
Mount-weazels
Mount-weazel
\stopexceptions
\starttext
\hyphenatedword{Schwarzenegger} \\
\hyphenatedword{Mountweazel} \\
\hyphenatedword{Mountweazels} \\
\hyphenatedword{epigraph} \\
\hyphenatedword{epigraphs}
\stoptext

Rik