I fitted some replacement LED bulbs to the DRLs today, and in the process of doing so had the bonnet open and started the stopped the engine a lot.... I noticed that "things" would start making noises on the turn of the ignition which certainly sounded like the fan, but it was always the same, so personally I would not worry, as per my comment quoted above, plus with the computerisation of cars, there is so much pre-checking of systems and functions, then as long as it is predictable, should be ok.
Ref strange noises ... Could this be a warning noise with one of the non-classic sound settings enabled? As mentioned, I replaced the bulbs, and when I turned on the lights for the first time afterwards to check, it sounded like I was getting a short-circuit and something burning up!! Ignition off fast and checked bulb. Turned out the lights-on warning when the "jungle" sounds are enabled sound just like a burning up noise (to me anyway) - could your noise be down to something similar?