vmware view connection broker stop responding on port 443

Hi

time to time (mostly 4hr a part ) my connection broker port 443 goes down and it take 3min to come back up , 

at the time it happened  i see this errors on View log 

2015-01-26T15:44:32.712-05:00 WARN  (116C-0BDC) <HTTPS Connection Processor> [PooledProcessor] Connection processor pool full - new connections may not be handled quickly

did any one else have such issue before ?

more info for the setup :

We are using View 5.3.1 and we have 2 connection broker  (active  and passive setup ) , for health check and load balancing we using  F5 

F5 version is 11.4.1

thank you for help