Operating system: Mac
Graphics card: Intel GPU
I first import a model and rig from a VRM file using (https://github.com/iCyP/VRM_IMPORTER_for_Blender2_8)
After navigating around (I do not change anything, I simply select random bones and what not. I see no consistency to the direct cause of this phenomena), the icons on the Viewport's camera controls for navigating the viewport dissapear (All 4 icons for pan/zoom/etc)
I have no idea if the VRM importer itself triggers this phenomena, or if it always happens, because I have not ever used blender before today.