Compile for Epub3 not validating epubcheck


I have an error compiling to epub3 and don’t know how to fix it. I make the epub as a zip file, extracted and look to the code. The line with error it is the line where “CHAPTER” title is in a

tag. If I change that to a H1 or H2 tag the error still persist.
The funny thing is that I compilled another project in epub3 format and no error on epubcheck. Create new pages in the project with no errors, delete the old pages compile as epub3 error appears. If I compile in epub2 no error. File parse the epubcheck.
Does anybody know how this error can be fixed?

Thank you.

Having similar issues validating epub, with a similar error appearing after updating to the latest 3.01 version of Scrivener.

I posted on the forum here, if you want to follow that thread in case somebody provides a solution:

Easier workaround: viewtopic.php?p=255893#p255893