First of all, in an unelevated shell it just shows "A general error has occured" without more specific message (like Windows PowerShell does, from this message it is possible to understand that we got an ACCESS DENIED error).
Now, in an elevated shell the table formatting is buggy. I.e. for Get-DedupStatus the columns "FreeSpace" and "SavedSpace" are just empty (while they are filled in Windows PowerShell), the same for Get-DedupVolume (columns SavedSpace and SavingsRate are empty) and Get-DedupSchedule (column "StartTime" is also empty).
The module seems to work fine when importing it with -SkipEditionCheck, so it seems like something is breaking when loading through the WinCompat layer.
This is basically the same issue as https://github.com/PowerShell/PowerShell/issues/12702 - just reposting it here for tracking after a tip from @rjmholt.
The module seems to work fine when importing it with -SkipEditionCheck, so it seems like something is breaking when loading through the WinCompat layer.