Operating system: Windows 10
Short description of error
glTF Exporter won't properly export linked collections if 'Selected objects' option is toggled and those collections are selected. This use to work as intended before 2.83.
The .glb do get exported but the objects in linked collections are not in the file.
Exact steps for others to reproduce the error
Create a .blend with any object under a collection and save. Create new blend, link the previous collection, try to export it with 'Selected objects' option toggled. Test the .glb in a viewer like this one https://gltf-viewer.donmccurdy.com/
(Note that I've only tested for .glb, this might still work for .gltf)