Did a search and this is exactly the same problem I have. A reply said that there is open XHTML in a post possibly… and suggested to go to settings, writing, and click “WordPress should correct invalidly nested XHTML automatically” Did that— still have the problem. Help please!?!
My home page on my blog is essentially a feed of all of my posts, and the layout has completely messed up. On the home page, you can’t see the sidebar until you scroll all the way down to the bottom of the page. Then when you scroll down and press the button “click for older posts”, everything seems fine. Scroll down again and then press “click for older posts again….we see that not only is the sidebar gone, but TWO POSTS ARE LAYERED of one another! Not only this, but when you scroll down further, all of the posts then lose their alignment and are no longer in the center of the page.