I have strange problem with Xbox One UWP (not xaml).
I run it remotely with Visual Studio and the first time it installs on Xbox and starts ok with these values:
Window.ClientBounds.Width and Height: 1920 on 1080
GraphicsDevice.Viewport.Width and Height: 1280 on 720
GraphicsDevice.Adapter.CurrentDisplayMode.Width and Height: 1920 on 1080
BUT every other time I run it, from Xbox directly or by building it again in Visual Studio, the Window.ClientBounds.Width and Height have strange values - 1728 on 972 - 10% smaller resolution which makes the screen zoomed in. Uninstalling the game from xbox doesn’t help, but restarting Visual Studio and running it again does, but only the first time. Even if I restart Xbox, it doesnt work.
I am using render target which works perfectly fine with OpenGL version and also UWP on Windows.
I have tested it on Monogame 3.8 and also new 3.8.1