subdomain added,but it can't be found in cpanel

I added a subdomain bbs.mydomain.com in cpanel,it returned the successful message,but it couldn't be found in subdomain list.
this subdomain can not be found in whm,also.

another subdomain flash.mydomain.com is listed in subdmain list. so inconceivable.

is there someone can fix it?

 

the subdomain bbs.mydomain.com works fine.
after deleted the subdomain and top-level domain, park the top-level domain and add subdomain again,the problem still.