Error during loading a form

May you kindly help, I’m seeing this error: Error Message:
"Failed to execute 'insertAdjacentHTML' on 'Element': The provided markup is invalid XML, and therefore cannot be inserted into an XML document.". How do i fix this problem?

@guineacookstove, could you kindly share with us a screenshot of your issue so that we could understand it pictorially and help you out? BTW, please also let us know on when do you see this error message.