HTML editor breaks code by removing line breaks, causing it to exceed RFC's maximum line length for emails
Just as the topic states. When adding code directly to the HTML editor, line breaks are removed when switching to WYSIWYG view or saving the template.
RFC 2822 states that the maximum line length for an email should be no longer than 998 characters.
If the resulting line in the email is longer than 998 characters, email servers and programs will break the line at that point.
If the 998 break occurs in an inopportune place, which it usually does, the final email delivered to clients will be broken.
Example attached. The vertical-align value is broken in two by such a break. When I added the code to the editor, there were manual line breaks after each closing a tag. After saving the template, those line breaks were removed, resulting in a line much too long for email.