This sounds lile you habe 2 copies of FSLTL installed.
Check the download location in the FlyByWire installer.
Thats where you updated to the current version that spawns traffic correctly.
And then go to your community folder
There you will find an outsated version that only spawns ground traffic.
I would suggest to delete that outdated copy and then update the path in your exe.xml to point to the current version.
That way FSLT will start with MSFS and use the current version that you can always update woth the FlyByWire App.
Edit: just saw you use addon linker. Well, simply apply my suggestion above to the way addon linker works.
Currently you are linking the outdated version.
You will have to get the path where the FbW App is installing to into addon linker