Hi Magesh,
Pardon me for not replying back earlier. I think we have identified what was causing the StaticWireTap'ped service to be not invoked.
We had this staticWireTap action in the action pipeline where the first action was ensuring a Asynchronous delivery. Basically this Asynchronous delivery action had processException method, which upon exception rolls back the transaction. It seemed like, in case of unhappy path (that somewhere in the action pipeline there was an exception), the Static wire tap'ped service was not called - yes, I tested by having break points. It was probably queued to be called but was not called, possibly due to an exception in one of actions in the parent service. The wiretapped service was being called in case of happy path, without any issue.
We are probably going to remedy this by having another top level service whose job is to basically wiretap twice, once in to the parent service and have another wiretap to the service which needed to be wiretapped in first place.
Regards
Soltar