Where are you using geoip, did you configure it with aliases and firewall rules, or through the IPS? There was documentation at one point instructing to configure with the IPS. This is outdated and the new recommended method is through using aliases and firewall rules.
Maybe this issue is caused by table overflow due to spikes in GeoIP lists.Franco mentioned this here: https://forum.opnsense.org/index.php?topic=24324.0Had a similar issue; setting max table entries to 4 million solved this issue for me.
We will be adding a counter in a 21.7.x release so you can see the table entry usage and if the tables are full...