Yes there have been AIRPOXs in C because someone screwed up, not because the system was working as intended.
If the airspace had been C as it had been before and after the misadventure into E then the AIRPROX would not have happened. The change to E was the major contributing factor. I'm being a little fast & lose with language because Dick does it all the time.
Looking at the definition of F the service we provide is far closer to that than G.