When I use flushright, my Japanese characters get widely spaced as if flushing right doesn't work
Minimal example:
% ===============================
\definefallbackfamily
[archimate]
[ss]
[Hiragino Sans]
[preset=range:japanese,
tf=style:W3,
it=style:W3,
bf=style:W5,
bi=style:W5,
force=yes]
\definefontfamily [archimate] [ss] [Optima]
\setupbodyfont[archimate]
\startsetups [japanese]
\setscript [nihongo]
\stopsetups
\setuplanguage [ja] [setups=japanese]
\mainlanguage [ja]
\starttext
\setupindenting[none]
\setupindenting[no]
\framed[width=\textwidth,frame=off,align=flushleft]{作図：A bit of text}
\framed[width=\textwidth,frame=off,align=flushright]{作図：A bit of text}
\framed[width=\textwidth,frame=off,align=flushright]{作図: A bit of text}
\framed[width=\textwidth,frame=off]{作図: A bit of text}
\stoptext
% ===============================
Output: