After upgrade to 5.2.4 plugging anything into wan2 shuts wan1 down

[ZeroInterrupt]

I have noticed this in 2 separate instances at 2 separate clients.  I upgrade to 5.2.4 and attempt to configure a second wan connection on WAN2 and within minutes of me just plugging into WAN2 everyone looses internet. No policies nor routing have been configured, I just plug in the secondary internet connection and I get a litany of calls asking what I did to the internet. Anyone else experience this?

[gschmitt]

What type of connection is set on wan2?

PPPoE? DHCP? Anything that could populate the Routing table without configuration?

Check the routing monitor for routes when the cable is plugged in.

[Diabolicus23]

FortiOS 5.2.4 has a recognized bug with 2 ISP (2 default routes).

Don't use it, revert the conf to 5.2.3 and wait the next 5.2.5