I noticed, while conducting a quick arrival-departure turn in my A350 that the engine sound was bugged out. When pushing back, I started the engines and because they were hot from the recent arrival, they spent 20 seconds or so "cooling", just running the starter motor without any fuel flow. It's a nice touch that this is simulated on the aircraft, however there's an issue with the sound. While sitting in the cockpit view, the full engine startup sound played even though the engines hadn't actually started. When fuel was finally introduced and the engines actually spooled up, there was no difference in sound. The motoring procedure finished and fuel was introduced all while the normal idle sound was playing. It's a small gripe but was definitely noticeable, and it'd be great if this could be fixed in a future patch.