Changing the file to EGJJ.BGL makes the file to be ignored.
That seems to indicate you don't have the SU10 Navdata option enabled in GSX, because if you have, the .BGL line in the .INI is completely ignored, precisely because when the Navdata is used, GSX no longer knows which .BGL has been loaded, it doesn't even look in the Community folder anymore so, if you see any difference when editing the .BGL pathname, it can only be due to not having the Navdata Enabled.
When Navdata is Disabled, instead, the .BGL filename ( NOT THE PATH!! ) will matter so yes, it's normal the file will be ignored if you change the .BGL name,
When When Navdata is Enabled, the only thing that matters is the ICAO code, which is the first part of the name of the .INI itself before the dash. GSX will load it if the ICAO matches the airport you are in, and if no parking spots in the .INI matches what GSX is receiving FROM THE SIM, it will give that error, because those parking spots in the .INI don't really exist in the data that came with Simconnect.
Note that, if you have a scenery conflict for any reason, using the Navdata will inherit that, including conflicts. Without the Navdata, at least, GSX always read ONE single .BGL so, assuming it read the right one, you could be reasonably sure it should match the .INI it was associated with. But when the Navdata is enabled, if there are conflicting sceneries for the same airport, or errors in the airport itself, GSX will get everything, including errors.