Basically, if you have an unsaved change on a page, and you try to navigate to another builder, the Save button will stay Yellow and you’ll be told you have unsaved changes on each subsequent page – even if you don’t make changes.
Repro:
- Load a builder, and make one tiny change on the page
- Note that the Save button is now yellow
- Open the hamburger menu, and choose Header, Footer, Content, or Layout
- Click the edit button on one of the available pages/layouts
- When prompted that you have unsaved changes, select “Yes, Proceed”
Observed:
When the next page/layout loads, the save button will immediately be Yellow. If you now switch to yet another page/layout, you will again be prompted that you have unsaved changes (even if you didn’t make any changes). And so on and so on. (See video below)
I’m not sure what changes it thinks are unsaved. After recording that video, I went back and tried an experiment where I made an obvious change on the first page. Then went through two more pages, and finally clicked Save. Then, I went back to the first page, and that obvious change wasn’t saved. 
By the way, moving through pages/layouts when all changes are Saved works fine. It’s just if there’s an unsaved change somewhere in there that it gets weird.