It seems to be more than just a drawing issue as it persists when I reload the page, duplicate the element, or publish the page and then reload. The only way to get rid of it is to make a new element and redesign it and enter the content, paste the styles, then delete the one with the null error.
Could you open console and then close/open again the settings, the error should appear there, just take screenshot and I’ll be able to identify the issue.