In reply to Justin Tadlock.

Yes, it also adds a lot of line feeds. This seems random in that there can be a different number line feeds between pars. In practice it relates to the amount of HTML comments.

It happened with short codes, but manually editing them wasn’t hard, with Gutenberg the cruft can be as much as 50 percent of the content.

I work with a publisher who has a custom made CMS that chokes on the line feeds and comments, so my whinge is specific to me, but I expect it can also cause problems for others.