Hi,
This is a bug I noticed in v2:
When entering a long list of text (with text processing on using any exhibition format) I was unable to save any edits or even preview the page. After searching on here for clues I thought it was a caching error, so cleared cache and tested in different browsers, but still I couldn't save or preview.
From what I can tell the root of the problem was caused by a line of text wrapped in a 'strong' tag, then a blank line, then another line of text opening in another 'strong' tag.
I deleted the closing strong tag from the first line and the opening strong tag from the following line, and was immediately able to save/preview.
Perhaps it was bad markup on my part but it might be useful if other people experience the same thing. A quick test and it's the same issue with other text styling (underline, italic, highlight etc).