Which is why american style manuals will always ask you to merge it with the subsequent word, without a hyphen You used the dash in the wrong place I might be tempted to create an open compound, but non doesn’t stand alone. Suppose that we want to negate a generic compound adjective adjective1 adjective2 Leaving non stranded doesn't work either as it is a bound morpheme, a prefix not a word (in english) I'd use the two hyphens.
OPEN
