LuaTeX-ja adds spurious space after curly quotes
In fact, LuaTeX-ja treats curly quotes as JAchars (Japanese characters) by default, because they have also codepoints in Japanese character codes). The same applies for some characters in "General Punctation" Unicode block (Wikipedia), such as dashes, per mille sign, bullet, etc.
Adding
\ltjsetparameter{jacharrange={-9}}should resolve the issue.
Adding {{{ \ltjsetparameter{jacharrange={-9}} }}} should resolve the issue.
This workaround does the trick indeed, thanks.
But is there a plan for a solution that doesn't resort to a workaround?
As shown by the following MCE, LuaTeX-ja adds spurious space after curly quotes (straight quotes are OK):