"a Matter on" implies: "an issue on The subject of" and so can only be utilized when one can insert the phrase "The subject of" after the "on", even though "an issue about" can utilized in advance of anything. Can we say "an disease /a situation/ a task... is fussy" https://cesarboygl.tokka-blog.com/36807345/hoodies-manufacturers-in-pakistan-can-be-fun-for-anyone