Yes. I ruled this out on the last time I was present.
SSH attempts didn't magically make the firewall pass traffic on the native interface again, as it appeared to have in October.
During the last ten minute span the "event" occurred I noted this:
The switch port the firewall is plugged in to never went "down"
ARP requests to the IP of that interface came back empty when requested by a workstation on that VLAN.
I could not ping the firewall interface IP
Traffic passing over VLAN2 to the internet (same physical ingress interface) was unaffected.
Traffic passing over VLAN3 to the internet (again same physical ingress interface) was unaffected.
SSH attempts didn't "wake up" the interface (didn't expect them to but had to rule out the coincidence)
I updated to the latest firmware and rebooted. So lets see what happens.