Duplicated entry in persistent table

Hi, I'm trying to figure out how F5 persistent works.

 

 

I'm load balancing between two servers and I need the client pinned to one server. Sometimes, the F5 get a miss in the persistent table lookup and F5 forward the request to the other server and a duplicated entry is persisted.

 

 

192.168.10.57 Source Address Affinity vip_aluiprod pool_alui_prod 192.168.10.106:80 45 seconds

 

192.168.10.57 Source Address Affinity vip_aluiprod pool_alui_prod 192.168.10.104:80 165 seconds

 

 

The same behavior is seen when I use the JSESSIONID as persistent key

 

 

1FxRMK1HBLpXBkskQyzpLZ6LTHDQ18xvdVrjLh8twX32QbmlXrfq!955383801 Universal vip_aluiprod pool_alui_prod 192.168.10.106:80 644

 

1JfcMKnLjPGDLBdqTSpd16JRQMShFLBM3Td0q1ddgwz57xGzz5cs!955383801 Universal vip_aluiprod pool_alui_prod 192.168.10.104:80 337

 

 

Is it a normal behavior? I have more evidence if someone needs to give me a response.

 

 

Thank you in advance!!