Font formatting causing problems / breaking template?

When I write a post using the inbuilt WYSIWYG editor, I find by the end that I am seemingly writing in mandatory bold, or I can’t seperate paragraphs. The only odd thing I’ve noticed is that the Path: list along the bottom of the WYSIWYG editor is rather long, such;

Path: div » span » div » span » div » span » span » span » span » strong » strong » strong » span

Am I doing something wrong, and how can I stop this happening again? It keeps breaking my theme.