From the SharePoint library, click the PowerApps dropdown and select to create an app
Pwerapps will create a new app with three screens.
Add a new empty screen named "Other Screen"
On Other Screen, add a button, and set its OnSelect to: Navigate(EditScreen1,ScreenTransition.Cover)
click on editscreen1
Remove the attachments field, and resize the form to make it a bit smaller so there is room for a button at the bottom of the screen.
Add a button to editscreen1, and set its OnSelect to: Navigate('Other Screen',ScreenTransition.None)
Save and publish the app. Then, click share to get to the screen with the url, copy it and navigate to that url to view the app.
Click to create a new row (the plus sign button), enter a title and amount, and click the newly added button to get to the other screen. Right before the navigation occurs, the title and amount fields will be cleared. Once on the other screen, click the button to get back to the edit form, and the fields are empty.
Enter in a title and amount once more, and try again. This second and following times, the values will be preserved.
I expect field values to be preserved while navigating. I also expect behavior to be consistent and not change if I click the same button twice.