@Ismael
I copied the php page into the old file. Then I downloaded the file and renamed it to asset-manager.class.php. Neither worked.
For now the only solution was to disable “CSS file merging an compression”.
Does that slow down the site much?
Sure Link to image below (private)
It might be a faulty export of the Enfold theme settings. (link private)
Importing the theme settings into an other site gave the same results. (link private)