RapidWeaver has a built-in auto-formatting feature. The feature if very handy to have, though conflicts with HTML code occasionally and in a way that is a little tricky to spot for new users.
What will occur is the quotation marks will format and style themselves to look nice for text. They will appear curly on closer inspection instead of straight up and down. This will cause a conflict and the HTML tag will break. The example quotation mark in the corner is the example that you want – straight not curly.
Unfortunately to identify this you’ll either have to have great eyesight, get very close to the screen, or use CMD + + to enlarge the text after you’ve first highlighted it. Remember how many times you have clicked the CMD + + command because you’ll then have to CMD + – that many times to return it to size if you want your Edit Mode layout to look pretty.
To protect this from occurring highlight all HTML and use the built-in Ignore Formatting command CMD + . That will not always protect, but has helped me in many occasions and is a best practice I always recommend.