snatpool vs snat

Hi, I have a problem when specifying the snat before passing traffic to another virtual server.

 

 

The version using is 9.4.7

 

 

As below, I found that option 1 doesn't work, the source address remains unchanged, but option 2 works fine. Is it a normal behavior?

 

 

Thanks.

 

 

snatpool snatpool_10.10.10.10 {

 

members 10.10.10.10

 

}

 

 

rule iRule_1 {

 

when CLIENT_ACCEPTED {

 

snatpool snatpool_10.10.10.10 option 1

 

snat 10.10.10.10 option 2

 

virtual vs_2

 

}

 

}