Photoshop only using alternate characters

Hi everyone,

I am running Photoshop CC 20.0.6 on a Mohave Mac.

I'm having trouble using Glyphs - the font I am trying to use has Glyphs associated with it, however photoshop will now only show text in its alternate form (ie the "fancy" character variants, not the regular characters). When I start a text bos, choose the font and type, all the letters are the "fancy" alternative letters. When I try to replace the "fancy" letters with regular letters it doesn't work, the "fancy" variants remain regardless of whether I highlight the character and then double click on the version of that letter I want to use in the Glyphs window, or if I delete the fancy one and then double click on the plain version in the Glyphs window.

It's a bit hard to explain, but I hope it makes sense! Thank you!