Interfaces swapping after reboot

[dibun]

I have HW from Pcengines and it has 3 ports

1. WAN (1st port)
2. LAN (2nd port)
3. DMZ (3rd port)
4. Guest (VLAN on LAN port)

Recently during one of the reboots the interface has switched between LAN to Guest and naturally FW rules failed. Even traffic is going via Guest interface instead of LAN
I did reinstall and configured from scratched and it worked but now it happened again and I did restore it from a good working backup but that didn't solve the issue.

I am running the latest production release.

Any help is really appreciated

[Steven]

You can reassign the interfaces from the Web GUI (Interfaces -> Assignments) or console. No need to reinstall.

Also do you have the interface locked to prevent interface removal?

Not sure why the interface would switch.

[dibun]

All the issue started after I tried to lock the interface. On CLI or GUI interface seems to be fine but the traffic has swapped according to the FW rules. Before the traffic was going via LAN interface and now it uses the Guest VLAN interface. It works if I stop the FW.