I checked it, and it doesn't happen here. GSX will never set the passengers before boarding and it still not doing it now, so nothing change.
However, the Fenix normally synchronize the passengers with the status from its EFB so, if you start a flight with the Fenix and the EFB is showing a non-zero number of passengers, those would be enabled in the seats automatically by the Fenix code, it has always been like this. I started a flight, and the Fenix EFB shows 0 passengers boarded, so there are no passengers visible as expected.