Differnet ping tests goes out over the same link?

We have a peplink with two incoming WAN connections. In the web admin I go to System, then Tools in the margin and click Ping. It shows the two connections. When I ping out over either one the ICMP packets always go out over the first connection. I can never ping from the second connection. Does anyone know if this is expected behavior?

Model: 310
Hardware Rev.: 1
Firmware: 5.2.2 build 1396

I tried the latest firmware 5.4.4 and it still does the same thing. Any connection I choose for the ping test the packets always come from the same IP (the first connection). Is this suppose to happen?

If you just send a regular (once every 2 second ping), then its only handling a single ICMP packet … every two seconds. Even a traceroute is the same

If you use something like PingPlotter or WinMTR, then they send out 20 or 30 packets in a block. They get sent out different WAN’s, but then because each WAN path length are different, the return results are all confused. Hence you add a rule to always send ICMP on a persistant WAN per destination.

Why in the web interface have a Connection drop down so I can select the connection when doing a Ping then?