When starting a bhyveload-backed VM with "vm start -f XXX", the last message you see is
boot/kernel/kernel text=0x1564b08 data=0x145330+0x4cdea0 syms=[0x8+0x16dad8+0x8+0x186a33]
and then silence.
The VM seems to be running below the event horizon, you can ping or ssh into it.
Workaround: never use the "start -f" mode, start normally and then use "vm console XXX".
vm-bhyve-1.3.0 on a FreeBSD 12.1 amd64 host.
This is a duplicate of the same issue in https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=240178
Unfortunately it looks like the way we were redirecting error output to file was incredibly ugly and broken, but worked because the way bhyve handling stio was also ugly and incorrect.
This was eventually fixed in bhyve which broke vm-bhyve.
The issue has been fixed in vm-bhyve-1.4.2, which has an open bug report to be committed to ports