For example:

>that achievement of eating only seaweed for 3 days inside the game.

>feed the furnace using lava bucket

>create more coal using tree trunks

>pass 1x1 using elytra over 40m

as I recall, these achievements are not working here (even if the world is 100% anti add-ons or cheat.) maybe there are more achievements that don't work that I don't remember mentioning here now, hope they fix this bug because I stopped us 80%