Reproduction:

• start MaterialDesignDemo app from the Demos folder in the solution
• switch to Cards view and check color of the Flipper and its child ColorZone being violet and lime accent
• then change palette in palette view to a different color for accent and primary
• switch back to Cards view

Expectation:

• Flipper and its child ColorZone have the selected colors

Result:

• Flipper and its child ColorZone still have the old colors (violet and lime)

The issue can be verified in my own project too

• start the app
• click the globe in the window header
• view with flipper opens
• click brush in window header
• change color in the opening view for primary and accent
• click globe again
• flipper still has the same color