Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce RTX 2080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 451.67
Broken: version: 2.83.2, branch: master, commit date: 2020-07-09 05:50, hash: rB239fbf7d936f
Short description of error
If there's a Principled BSDF shader anywhere in the material in node editor, even if it's unconnected to anything, and have a Background node connected to surface it will ignore any connected images or colors and export blank white every time.
Exact steps for others to reproduce the error
Make a material, unconnect the Principled BSDF node from material output, change surface type of the material to "Background", change the color or connect a image texture in node editor. File > Export > gltf 2.0, export with materials selected. Import the .glb into another program or back into blender, the texture wasn't exported and the color of the Background node is ignored and will appear pure white.