Losing connectivity & arp.core file in /

[IShouldHaveBeenAQATester]

[ X ] I have read the contributing guide lines at https://github.com/opnsense/core/blob/master/CONTRIBUTING.md
[ X ] I have searched the existing issues and I am convinced that mine is new.

Describe the bug

After updating to 21.1.2-amd64, I now am occasionally losing connecitivy through the firewall and an arp.core is being generated in /

To Reproduce

I am not sure. I can't reproduce this consistently, although I may be able to help when it occurs again. Just give me instructions on how to assist. I only have a 4GB filesystem for my opnsense machine so I've already deleted 2 arp.core files already as I'd otherwise have a full filesystem. If you'd like me to save these the next time this happens, let me know.

Expected behavior

No /arp.core file and connectivity to be maintained.

Describe alternatives you considered

I've tried restarting my cable modem, and also tried restarting all services from the CLI on the opnsense machine. This machine is a VM with hardware pci passthrough using an sfxge nic + vlan tagging. Prior to 21.1.2 I've never seen this happen. I originally opened a thread here: https://forum.opnsense.org/index.php?topic=21926.0 but was asked to open an issue on github.

[fichtner]

Sure, cherry-picked as 3ea5bed and will be part of 21.1.3 next week. Thanks a lot!