Why is my content being wrapped by HTML <code> tags?

Figured it out. For some reason, when I pasted the shortcode into the visual editor, it was being wrapped in code tags. Probably because the shortcode is wrapped in code tags on Bill’s website. (Indeed, this is the reason)

Anyway, I couldn’t see the code tags in the visual editor, but I noticed that the shortcode was in a monospaced font, even though I had the paragraph style selected in the dropdown. I simply switched from visual to text mode, deleted the rogue code tags that I found, and all was well.