Hi Karl,
Many of our sceneries put the traffic BGLs inside the specific scenery folder. Some of our sceneries (e.g. AI Shipping Package) put the traffic BGLs in Scenery\World\Scenery. It depends on the scenery addon's design as to how the traffic BGL is being used.
Some of our traffic BGLs are seasonal and will not work with the eSwitcher if they are put in Scenery\World\Scenery. If all of your RTMM sceneries are up to date, there should not be any Seasonal sceneries in Scenery\World\Scenery Bottom line, you need to follow each scenery's installation instructions.
If you do a search and find the same traffic .bgl in two different folders, then most likely one of the folders is a regular scenery addon folder and one of them is Scenery\World\Scenery. Normally, I would then get rid of the one in Scenery\World\Scenery. When in doubt, consult the latest version of a particular scenery addon's installation instructions from our Scenery Library to see where the traffic BGL (s) belongs.
You are correct that you should not have the same traffic BGL existing in more than one place.
Rod