There is a bug I found trying out Confluence sandbox (http://sandbox.onconfluence.com)
Steps to reproduce:
1. Create a multilevel list in RTF editor
2. Select entire list and change it's color using color selection panel
3. Switch to Wiki Markup
-> Structure of lines is broken
4. Then switch to preview or save ticket
-> List is corrupted (see attached screen)

There is no way to avoid this problem other then do not use colors...

Problem is browser independent.