Font doesn't recognize European and Russian glyphs

I am working on a Slab Serif Display font loosely inspired by Russian propaganda posters.
Of course that means Russian glyphs are a must.

(1) I drew them and named them in the layers panel like all the others.
(2) Transferred them into Fontself and they seemed to be accepted.
After Smart Kerning did its thing, I then named it and saved it as .otf.
(3) When I looked at it in Font viewer it was obvious that not all the glyphs were viewable.
After installation I could see the glyphs in the Glyphs panel but couldn’t use them in Text.
I pulled in some Russian from Google translate and tried to change the font but it simply reverted back to the original Font every time.

Any ideas on how to fix this?

Sounds like a font caching issue (many apps or operating systems keep the first version of a font in memory even if you update it), so try to delete/uninstall the font first, and reinstall the newer version again: https://help.fontself.com/en/articles/915125-install-vs-save-export-fonts