Hi Toufiq,
I have fixed all the problems with the headings!
That here code was deposited, as I have shown it in the graphic, reported to me my SEO program Seobility.de used by me - it showed after the scan many pages (all new created by me since the change to the new SP Page Builder version) with many empty headings.
Strangely, this code is not visible in the Text AddOn under Code, only when I scan the page with the Inspector or look at the source code.
To get rid of this problem I usually had to replace the whole line - finally I copied the line from a "clean" page, pasted it into the page I wanted to edit and adjusted the text in the Text AddOn again, then deleted the "contaminated" line - a lot of work!
Currently I have only one example page saved where you can see the problem - and I have to correct myself, no matter if I insert a H2 or H3 heading or even normal text in the existing or in a new Text AddOn - in the source code I get the entries "section data-mce-style=" or "h1 data-mce-style=" shown and quite a lot of them!
The example is the SP Page Builder page with ID 126
Greetings - Marco