And the reason was invalid /boot/loader.conf:

console="vidconsole,comconsole" autoboot_delay="10" console="comconsole,vidconsole" autoboot_delay="1"

Second console actually disables access from web console access, which is fatal.

Autoboot is not critical, although default to 3 sec should work much better for opportunity to change boot options from web console.

This got apparently fixed, in my "ams3" instance I've had to issues getting web console to work (needed to "tunefs -n enable /")