Why is the CPU Monitor on the ProxySG reporting high CPU utilization in HTTP?
The most common reason for seeing high CPU in HTTP is because of load due to a routing loop or too many incoming requests.
Using the management console, verify the bandwidth using the Statistics->Traffic Mix section. Confirm if the processed bandwidth for the SG is "typical" for the ProxySG or if it corresponds to the CPU spikes. If there is a correlation, lower the amount of bandwidth that the ProxySG processes and see if the CPU drops.