Embed-server from CLI launch shows twice prompt string

When I launch an embed-server from CLI, it displays twice [standalone@embedded /] [standalone@embedded /] for the first time.

[wangc@dhcp-128-40 wildfly-10.0.0.Final-SNAPSHOT]$ sh bin/jboss-cli.sh 
You are disconnected at the moment. Type 'connect' to connect to the server or 'help' for the list of supported commands.
[disconnected /] embed-server 
[standalone@embedded /] [standalone@embedded /] ls  
core-service                               launch-type=EMBEDDED                       product-version=undefined                  
deployment                                 management-major-version=4                 profile-name=undefined                     
deployment-overlay                         management-micro-version=0                 release-codename=Kenny                     
extension                                  management-minor-version=0                 release-version=2.0.5.Final                
interface                                  name=dhcp-128-40                           running-mode=ADMIN_ONLY                    
path                                       namespaces=[]                              schema-locations=[]                        
socket-binding-group                       organization=undefined                     server-state=running                       
subsystem                                  process-type=Server                        suspend-state=RUNNING                      
system-property                            product-name=undefined                     uuid=8c4ede2f-8e14-48bf-9eaf-73947e23edcf  

[standalone@embedded /] quit