Just had this issue last night:
Turned off HTML Tidy, next thing I know all text after the <p> tags jumped down a line and indented to where the <p> was. I then checked the following html pages to see if the same thing happened to them... nope... instead all lines lost their (your) left hand spacing/indents. So in other words they were all right aligned.
I went back to the page I was working on, fixed up all the <p> tags by removing the extra line and the extra indents. Saved. Closed the epub, went back in to the page and it was back to the extra line and indents. Haven't attempted to fix the other pages with no indents. Figure I'll just have to go back to pre-beta, as that bug is just too annoying.