David Selin

Daniel: Strange problem. Are you signed in to Xbox and Minecraft with your windows login? And do you see your gametag in both Minecarft (start screen) and Xbox?

Daniel: Ok, so have this world ever been a creative world? If you do not have the "Bake Bread" achievement, start a new world and grow wheat for the bread and you should get the achievement if you don't ever set the world to creative

Daniel: Have you tried to move your other saves temporarily and then check that difficulty is set and that you have a survival map? Are you running on a windows 10 device?

this is related to report about Android version MCPE-10726

Strange that I can't link or close this and add Win 10 PC edition to that report. Should be a feature of a bug-tracker.

If the game has been switched to creative you will no longer get achievements for that world. Other worlds and new survival ones should be OK.
I don't know if changing difficulty settings will do this as well. I find it a little irritating that it sticks for your game and not world.

I even made a zip-file of a world, changed it to creative, flew around and changed stuff, renamed it and restored the original world from zip and still get new achievements. So it should be in the world save and not the game.

I have played a survival game, started a create and gone back to survival and can still unlock achievements (win 10 PC). As soon as the world has been tampered with it is banned from achievements.