As a number of folks who've decided to emerge from Vault 111 again have been reporting (thanks, TrueAchievements), Fallout 4's achievements on Xbox aren't doing what they should be.
Bethesda already looks to be aware of the problems, with a support article being live that says the developer is 'currently investigating' the issue.
The article suggests you do a few checks before reporting it as a bug, just to make sure the issue isn't on your end.
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