Agents login the queue and i can't logout from queue

dears ,

have a good day , i have a call center using FreePBX 2.5.1.2 (every agent have to login in the queue to receive calls ) i have only 2 extension receive calls without login i try to logout them but they still receiving calls without login and i checked in the queue there is no static agent after i checked i found that 2 extensions view as (SIP/1604) but the other extensions view as (Local/[email protected]) so what is the difference between them and i need to know how to remove them from the queue ?

thank you