Ligatures don't seem to work?

I have added some custom glyphs to the standard ligature table using an open source font from Google. The ligatures show correctly in other applications, e.g. Word, and also appear in the glyph panel within Illustrator, but do not appear in text in Illustrator (or other Adobe applications).

My font file is attached. (Exporting from FontForge with either TTF or OTF yields the exact same result in both applications.)

Any ideas? Thank you 🙂