Only every other paragraph is marked with surrounding <p> tags.

This results in browsers rendering every other paragraph using the Confluence stylesheet's definition for a "paragraph" class and every other using the default settings. On some browsers, this results in the use of two different font sizes for body text of pages.

For example, in the following page all three paragraphs are rendered together with the first and the third paragraph being surrounded by <p>'s and the middle one just being nested in the middle.

http://confluence.atlassian.com/display/TEST/Paragraph+rendering+demo