Played game as normal, saved and quit four or five times before going to a realm to play, Too laggy to play so returned to single player. The game progress didn't seem to save correctly. Character was reset back to world spawn with no items. Issue appears to be intermittent, Was experiencing slower than usual internet at the time.

Issue would appear to be a duplicate of MCPE-25635 However it is not resolved.

Attempted to replicate on Win10, failed. Replicated on another Xbox one by another player.

EDIT: As per Auldrick this appears to be a duplicate of MCPE-29863