You can always try a font in Unity's built-in "Text Mesh" or "Text" (UI) components to see if it's just the font.
From what we discussed in the email, looks like that font is missing the zero-width space, or rather, HAS the zero width space and uses that character instead. will see if I can have STM fall back to arial just for that character... but can you edit that font? The soft hyphen appears to be missing/wrong, too