Issue with Stack Navigator

I have a small problem with the stack navigator. It happens in both Live Test on my phone as well as after I install the apk file on my phone. I have a navigation screen that has buttons that take the user to various other screens. If I navigate to one of the first 2 screens, the navigation arrow at the top of the screen (in the Stack Navigator) is visible. Also, after I navigate to one of the first 2 screens this arrow is visible on all screens. However, if I navigate to any of the other screens first after starting the app, the arrow is not visible. If I tap in the spot the arrow is supposed to be, it will still take me to the previous screen. If I then go to one of the first 2 screens, the arrow will start to appear on all screens. I think this must be a bug. Can anyone help? Thanks in advance!

Update: I changed the Header Text on my screens and moved screens around in the hierarchy and the arrow shows up on Live Test but it still does not show the arrow when I install the app on my phone until I visit one of the first two pages. Weird…