Those particular characters fail because I didn’t import them into the SDF font; it’s solvable if you want. I just didn’t import the whole character set to save space. You’d just add them here and re-render
Anyway yes, I will abandon the character set if it’s not solvable, I just found it strange that it didn’t work, and thought to post this question before giving up. I also wanted to ask in case my other languages also had characters built with a secondary overlay character.
My Polish localization team thought the small caps helped identify specifically used terms well, but we can find other approaches.