Load balanced -Observed with persistence

You'll need to change the persistence method. Destination address persistence will send all traffic for a given destination (in this case the vip) to a single pool member. You likely want to load balance clients across pool members and then have them persist to the member choosen in which case you need a persistence profile that identifies a returning client (as opposed to identifiying the destination for the traffic). Source address and http cookies are the most common methods for this type of persistence.