The distinction is particularly absurd at gate C18 where the GFL lounge's back door opens into the GS boarding line. Global First passenger coming from the lounge? No line for you. Global First passenger coming from the concourse? Wait behind everyone else. But United endeavors to deliver a consistent boarding experience, of course.
The agents in the IFL are more than happy to escort me to the front of the boarding line for the C18 gate through the back door. Perhaps it's just loveable me?