FRR routes sometimes disappear from system routing table

[PseudoResonance]

Main

I'm running OPNSense with FRR. I have some other FRR servers that are sharing routes via BGP to my routers, and all is fine, until a route just vanishes for some reason.
If I check FRR (the OPNSense UI or in vtysh), the route is still clearly listed

Routing entry for 192.168.10.0/24
  Known via "bgp", distance 20, metric 0, best
  Last update 00:10:38 ago
  * 10.115.1.1, via vlan015, weight 1

However when I check the actual system routing table, it's just not there.

When

This is most often a problem when I just restart the router, but also happens seemingly randomly over time.

Other

I'm running OPNSense in HA, with pfsync and XMLRPC sync, and XMLRPC is set to sync "FRR", but not the OPNSense "static routes". I thought maybe this is causing it somehow, but wasn't able to come to a solid conclusion.

Is there anything I can try checking or debugging to see why FRR's routing table seems to fall out of sync with the system?

[donaldsharp]

are you using systemd? https://scottstuff.net/posts/2025/02/25/frr-vs-systemd-networkd/

[PseudoResonance]

are you using systemd? https://scottstuff.net/posts/2025/02/25/frr-vs-systemd-networkd/

Nope, no systemd on FreeBSD/OPNSense.