CURRENT >r349150: boot failure in rc.conf.local

On all CURRENT boxes running CURRENT > r349150 we face the very same boot
failure, if /etc/rc.conf.local is present (i.e. on CURRENT, 13.0-CURRENT #7
r349169: Tue Jun 18 10:34:13 CEST 2019 amd64):

The box boots and thentries to start services denominated
in /etc/rc.conf.local, like net/openldap-server (slapd). The box is then stuck
at "startingt slapd", hitting Ctrl-T shows state "running", but Ctrl-C does not
show any effect, except Ctrl-Alt-Del (if enabled) is effectively rebooting the
box. First I thought it might by a out-of-sync binary, but this phenomenon
spreads even over recently via make installed systems. Disabling OpenLDAP's
slapd at boot time gives my like rolling a dice the next service, named
(dns/bind914) or net/samba48 (samba_server) - you name it. The box gets stuck
forever and doesn't even start sshd to provide access. All boxes have IPv6
enabled as well as IPFW.

Another server running CURRENT (r349169, also amd64) without
utilizing /etc/rc.conf.local but with a bunch of jails is booting as usual!

What happened here? Does anyone do have a hint or might know the cause?

Thanks in advance,

Oliver