I have a rooted Android One phone running Oreo 8.1 (Mi A1), but my previous rooted Oneplus 3 ha a similar problem.
My desktops all run Ubuntu 16.04. When I plug the phone in via the USB-C cable it comes up with an empty MTP window. In order to be able to copy stuff to and from my phone I need to go into developer options and tap the Select USB configuration, Then tap MTP - even though this is already set - which then shows up on the PC.
(Happens regardless of USB Debugging flag, Verify apps over USB is on)
Why is this happening, and is there any way to fix it, or even to add a button to the home screen to allow me to find this option without navigating deep into the settings?