Music on Hold class for queue

Hello, has someone faced (not sure if it a but or not)?
I had to configure a queue and setup a music on hold to be played to the caller when NO agents are available, I though that recording will be just played IF no agents are available, well that is not happening in may settings, the MoH is played even when there is available agents, further more, the MoH is played in parallel the agent is called. is that the way it should work?
any comments/suggestion will be appreciate.

Asterisk 1.4.36