Quite wild guess, though, if you're the registered maintainer && committer who committed it, email wouldn't be sent to you by default.
This is because "any action by oneself is NOT notified".
Usually, as far as I know, assignee is the committer who committed (and needed to be a committer) it.
If the registered non-group maintainer is a committer, the maintainer can be the assignee, too. This case, email stating "Closed Fixed" wouldn't sent to the maintainer (because the action is by the maintainer [him|her]self.
But if not, need another assignee. This case, once the assignee closes it, the maintainer would be notified.
