I've separated all sections in my document using "Section breaks".
So I have:
Chapter 1 =====section break====== Chapter 2
- First, I set the header for chapter 1.
- Then, I go to chapter 2, uncheck link to previous and try to change the header again. It then obstinately changes the header for the first section to "chapter 2".
Here's a sample document: https://www.dropbox.com/s/x2nxnfdhxk3e0so/Section%20breaks.docx