This seems to be a new behavior, but regardless it is a problem that breaks other frameworks that call out to the command line shell with a single command and expect it to return. Currently it fails to exit, and callers hang. This is true both in the case of the server running with a management interface, and when one is missing:

[269](ironmaiden:bin) > ./jboss-admin.sh --connect command=:shutdown
Connected to standalone controller at localhost:9999
Communication error: Channel closed
Closed connection to localhost:9999
^C

[270](ironmaiden:bin) > ./jboss-admin.sh --connect command=:shutdown
The controller is not available at localhost:9999
You are disconnected at the moment. Type 'connect' to connect to the server or 'help' for the list of supported commands.
^C

When running a mode where the commands to run are from a file or command line, that is, non-interactive mode, the cli should exit with a status.