SOLVED Auto SSL off, replaced hostname cert anyway

I have my own paid certificates for my hostnames, and have specifically turned off all settings in Cpanel/WHM I could find to replace or supply them at any point whatsoever. This morning I wake to complaints about the server certificate being replaced by the Cpanel version, while mine still has around 24 days on it.
Doesn't turning this off mean it's OFF?

Can someone explain what settings are responsible (all of them, since I hope it's just one I missed and not Cpanel ignoring the setting) for this?

 

Thanks. It would seem the file that prevents this had gone missing, since it was added back then. Search didn't find that thread (my own!). Tough day.