I've also seen issue where I add a gateway that does not appear in the gateways list but Dpinger is trying to monitor it and there is no way to remove the gateway now.https://forum.opnsense.org/index.php?topic=13602.0
should be fixed in a future release, https://github.com/opnsense/core/issues/3625 contains the steps to test earlier (on 19.7.2).
We should make the upgrade path 19.7.3 when it is released. I see FreeBSD has released new security advisories so the latest kernel would be better...Cheers,Franco