Stop packet filtering and clear state:
Reload rules:
If error persists, reboot system.
If still persists, ensure kernel/userland match:
If you maintain a custom kernel/module:
If you need to revert:
If you cannot reboot or match versions, flush PF entirely and start minimal: pf configuration incompatible with pf program version
pfctl -d
pfctl -F all
echo "pass out all" > /tmp/mini.conf
pfctl -f /tmp/mini.conf
pfctl -e
Then manually add rules one by one using pfctl -a to find the offending line.