Single-page Publisher documents don't automatically take on Master Page formatting... Again, I'm unsure if this is by design or a bug.
Scenario 1
Create a new one-page, facing-page document starting on either the left or right using the default master
Add a text frame to both the left and right master pages and link the two frames
Format the linked Master page text frames with text style
The Master page formatting is ignored by the single page even if the Master is re-applied to the page
Scenario 2
Create a new two-page, facing-page document starting on either the left or right using the default master
Add a text frame to both the left and right master pages and link the two frames
Format the linked Master page text frames with text style
The Master page formatting is recognised by both pages