While I do not seem to have the problem a couple of people have reported of an opening paragraph tag being inserted in front of img tags inside of divs and no closing tag. I definitely have the problem on my contact form (using Contact Form ][ plugin). It is inserting an opening p tag before every Label tag and Textarea tag and no closing tags. Those elements are in divs as is the whole form. It also inserts a closing p tag just before the closing form tag and then again just before the closing tag for the div the form is enclosed in and neither of those were opened.
And none of those p tags should be there. The form(surprisingly) still looks OK and functions fine but it doesn't validate. But it would be nice to have it corrected.
Other then that the upgrade went real well, I even busted out a new theme so everything is all shiny and new.