Greetings,
I was having no luck updating from either command line or the web gui-- OPNsense 16.7.13-amd64.
Solution: go to Services -> Intrusion Detection -> deselect IPS mode and then save.
system then updated with no problems.
Thanks for this great piece of software.
This sounds like offload is not disabled (this may require a reboot). Disable all hardware offload, reboot and enable IPS again. It should work then.