Ok, that is what I was thinking but the customized per Product field doesn’t allow any HTML, only text entry. I don’t see HTML editor active in that field when I edit a particular product.
I have CKEditor installed for Description field editing in HTML.
We see you are using a modification that brings back the CKEditor as a visual editor. The problem is that the editor initialization is for only the description field. You may need to get in touch with the extension developer to solve this.