Conditional Access: Can someone please explain sign-in frequency and persistent browser session

Has anyone had both working together?

Running some tests this afternoon - Persistent Browser Session for all apps, with a 2 hour SIF. A separate policy for PowerApps with a 1 hour SIF. Once the one hour SIF is hit, all applications not just Powerapps require re-authentication in the browser. 

Great if they would work independently but not sure if this is currently a thing!