Unfortunately, no, you're not missing anything re: config/safe mode. If you're not getting the flashes, or a message reporting that it is config mode on particle, then "Houston, we have a problem!"
From the log message you're getting, it looks like either for some reason the Oak is just constantly rebooting, or doesn't think it is successfully establishing a connection to Particle. It is similar to another problem that was happening with an earlier version of the Oak firmware, but IIRC it would consistently go online and then offline, and keep cycling for a while.
I think your best bet is to wait for that USB to serial adapter, and then do
the Easy Serial Update, and just restore the Oak back to stock. Hopefully it was just a once-off gremlin.