Hi Arphilyaw,
If possible, can you provide us the dbglogs when the issue occurs - load balancing with protocol binding.
To get the dbglog from SA520W, login through web UI and in the URL type
https://IP_address_of_SA520W/scgi-bin/dbglog.cgi (where IP_address_of_SA520W – is the IP address of the SA520W router).
These logs will store password, so please remove any password sensitive information. Also if you are not comfortable posting the dbglog on the community, you can send it directly to me through IM or email.
Thanks,
Nitin Manglik