I talked briefly to stoot about this in the game, but I recently gassified all of the individual gasses (and held onto some general vapour) in order to get the proper achievement and put them in my root inventory just so there'd be no confusion, but the achievement never fired.
Additionally, when I tried this for fruit yesterday, I again made all of the fruit and placed it into root inventory, but the achievement didn't trigger until I'd already given up and eaten a few of them/moved most of the rest into bags.
Again, for emphasis, I converted all of these items in today's and yesterday's tests.