Good advice - I did:
ss -ltpn |grep :80
LISTEN 0 511 *:80 *:* users:
(("apache2",pid=1051,fd=4),("apache2",pid=1023,fd=4),("apache2",pid=1020,fd=4))
wtf?
ps -fae |grep apache
root 1020 1 0 10:29 ? 00:00:00 /usr/sbin/apache2 -k start
www-data 1023 1020 0 10:29 ? 00:00:00 /usr/sbin/apache2 -k start
www-data 1051 1020 0 10:29 ? 00:00:00 /usr/sbin/apache2 -k start
WTF!!! I never installed apache2 - this system has been nginx from the start (–LEMP), and apache is deselected in features and plugins. If it somehow got installed anyway, it was never running until now. I removed apache2 and rebooted and everything was good - Still a mystery on how this could happen.
Thanks for your help guys, you saved the day!!!