Avia Layout Builder disappeared on page after revision -which didn't work either

So, I forgot to put my text into an editor before pasting it into a list inside a segment of the Layout Builder. Then something weird happened: terrible code between the segments,segments doubled, the width of the objects, which were in full width were in part boxed.

As I saw the mess, I did an revision to the page, but it did not work. That was not how the page was at that time about an hour ago and in addition I had only the wordpress editor, not the Avia Layout builder on that page. It had disappeared and I don’t know how to get it on that page again. The other pages still have WP-Editor and Avia. I don’t know what happened here at all.

The first thing to fix that crap would be, to get the Builder back on the page – but how?

Can someone please help?