Poster above me....it's because they aren't the same. One is a filament the other is a light emitting diode (LED) which has instant on/off characteristics...thus giving you the "not synchronized" conjecture.
To the OP
for doing this.
In my MKV I had to solder in a resister to fool cold diagnostic check into thinking there was enough resistence so it wouldn't through a bulb out light....good stuff