Unable to write Shavian letters in Illustrator

Been trying to write Shavian letters in illustrator, but even with the supported fonts, it shows up as missing glyphs. It even doubles the amount of glyphs, even though that isn't supposed to happen with Shavian.

𐑡𐑷𐑟 turns into whatever happens in the attached file. This happens with both Noto Shavian and Segoe Historic; two fonts that already support Shavian.

Any way to fix this?