I’m using the North Slavey Keyboard from Language Geek for transcriptions. It is Unicode based. However the glottal stop ɂ doesn’t show up (only a square) and the high tones and nasals on the i move one character to the left. Copy and Pasting into word shows the correct characters, so it seems to be a display problem?
Yes, this is most likely a font/display problem.
The square indicates that the font doesn’t contain that character, you could set a different font for the specific tier(s) and see if that helps? That might also solve the other problem (although I’m less sure about that).
-Han