We are using OCS 18.104.22.168 for our OJS User's event, coming up in June, if I'm correct.
I'm not responsible for the setup, and don't have access to it to be sure what is going on.
The Website configuration has a title image, as you can see here
When viewing the next event, the site title is showing, as you can see here
The same does not happen in the previous event, as you can see here
, probably because the alternate header is being used.
I haven't checked the code, but it seems to be adding the site title in every page.
Also, when editing the site configuration, it does NOT allow me to remove the site title as text, even if I have an image in the form.