When implementing Greek in a font, I realized that using the polytonic version some glyphs point instead to those of the monotonic version.
This happens both in LibreOffice and with LaTeX, although I specify the composition engine I use, namely Lualatex, the <polutonicogreek> option.
I state that the accents of monotonic and polytonic are slightly different.
The fact is that the glyphs (polythonic) with the grave accent, which should be those with oxia, point instead to the glyphs (monotonic) with tonos (unless I, instead of using keyboard shortcuts to write, directly enter the glyph with the correct unicode value).
Of course, this problem doesn't show up in the professional fonts I've checked, but I haven't found the same solutions. In some there is a lookup of ccmp, in others of the Contextual Alternates with replacement rules. But honestly, I didn't understand how to proceed.
How do you solve the problem of the correct coupling between monotonic and polytonic, precisely in relation to these accents?