Created attachment 202713 [details]
I got the following kernel panic which seems to originate from nd6_llinfo_timer
Operating system is running in VitualBox 5.2.26 with "Promiscuous mode" set to "Allow all"
I note that you're on 12.0-RELEASE-p2. -p3 contains a fix which is quite likely to address this panic. Please give it a try and re-open this bug if you're still seeing panics.
*** This bug has been marked as a duplicate of bug 234296 ***