VOIP failover not returning to preferred link

I have two PEPlinks at different sites and both exhibit the issue that should the preferred link go down fail over to a secondary, the VOIP connections don’t all return to the preferred after the service is restored.

This happens at both locations, one has a Balance 20 and the other has a Balance 380.

The config is as follows:
Algorithm: Priority
Priority Order: WAN: ISP 1
WAN: Mobile Internet (not used)
Terminate Sessions on Link Recovery: X Enable (tried it both ways)

So what happens is if ISP 1 goes down the VOIP sessions correctly transition to ISP 2 but long after ISP 1 comes back up the VOIP sessions do not transition back to ISP 2.

In this case ISP 2 is fast but has high latency and not ideal for VOIP and why I really want the VOIP session to return to ISP 1 as soon as possible.

Any ideas why it’s not doing so?

Please obtain the diagnostic report via http://www.peplink.com/index.php?view=faq&id=31&path=20

And submit the support ticket via http://www.peplink.com/contact/support/ with mention this forum post and let us know the IP addresses of your VoIP setup such as devices and servers.