In the previous one it marked my vegan as incorrect and similar question and vegan is correct. Is there a distinction in Welsh?
My previous question asked for 'vegetarian' not 'vegan'. Is it possible you got these confused?
I don't quite understand what the problem is here. In the above example 'figanaidd' is the adjective which describes the food, ie Bwyd figanaidd = Vegan food. A vegan as a noun would be 'figan' (although some spelling are 'fegan')