Horrible Logic7 sound - DSP haywire?

Have a 2008 335xi, with Logic 7 sound system.
Turned the car on, and what was usually that pretty-sounding chord "gong" (for the seatbelt reminder), came out as a horribly garbled, almost screechy
sounding noise.
Same happened when the "gong" went off for the freezing outdoor temperature warning - same awful noise.
When I turned the radio on, the audio sounded terrible - like a badly off-tuned scratchy AM radio station - regardless of whether I had it on AM, FM, or playing a CD. Basically un-listenable. Turned radio off/on, still the same. Car off/on, still the same.
It has worked fine before all that.
Turned the car off, locked it, let it sit for 5-10 min, and when I got back in and started it, everything was fine. The nice gong sound was back, and the radio sounded like it had before. Has been fine since (last day or so). As if something in the audio system had to reset itself.
I guess the best analogy I can make is that the radio sounded like a badly chopped-up digital cellphone call, as if the digital signal processing system in the Logic 7 hardware/firmware had temporarily gone haywire. As if the audio system had not quite "booted" properly when I started the car.
Went to the BMW dealer this AM, the SA told me that he has had a few customers come to him in the past with the same problem. Said that it doesn't happen very often, and suggested that a software upgrade might solve it. That's strange because I picked this new car up just two days ago. He was also not sure whether or not it gets logged as an error in the computer. You think it would have the latest software revision?!
I had heard about this problem on the E90Post forum about a year ago, but cannot find it now.
Anyone else experience this?
Thanks,
Mike
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You have had it two days - what is usual then?

Probably low volts or similar or just a glitch.

A new 3 series - not for many years :-((

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