Paragraphing problem happening again

Hi I have been watching this problem happen on and off with many sites, I’ve installed plugins on websites and sometimes they would work and sometimes they wouldn’t.

This time, I was just changing some information and it clumped all the text into one paragraph.. I didn’t even switch between visual and text editor, I didn’t do anything major.

When I go to a previous revision, it all just looks fine but if I make just one edit anywhere, it displays everything like this:
http://vinoandforte.com/concerts/

Anyone has any thoughts on how to remedy this?
Thanks