Mystery route that keeps coming back

[abenaou]

Hi all,

I have 2 opnsense firewalls, both running 25.7.8 and to each their vlan.
They're both interconnected by their LAN interfaces, in case WAN1 fails the traffic goes through the gateway of WAN2.
No the issue I have is that a route shows up on its own, I didn't create it, and when I delete it keeps coming back bringing my server down :
The faulty route is 10.99.200.180 being sent to 10.98.200.1 which goes through WAN2, I didn't add it and even when I delete it, it keeps coming back.
Can you please help?

Thanks