Font / css pb following the update

Hello,

I’m working on a site I didn’t developp and I see strange things on Enfold : I’ve just updated the theme (3.2 to 4.1.2). Everything seems to be OK escept the titles font. In Enfold interface, I’ve choser Quciksand, but on the site I see pantonsemibold (see first h6 on the homepage, just under the slider. And if I look at the css which is called, it’s custom.css instead of enfold.css
I also see strange presentation in the inferface, see print screens attached (I use Enfold on other sites and I don’t have the title overwritten or the red fields or “Set background” alone in the window.

It scares me because I wanted to changed of hosting this week-end, it failed due to Enfold, I thought it was because the theme was not updated but with those small issues I’m not confident.
I precise that the people who built the site are not developpers so for sure, they did’nt write in files or things like that.
Do you understand what’s going on with Enfold on this site ? I’m on WP 4.8.2.
Please find below the credentials.
Tx for your help guys
Marine