Plugging in USB when no battery in neo1973

[Patrick]

Hello,
yesterday I inserted the USB cable into the neo when no battery was in
the device. As i plugged it in the neo began to make a strange sound,
kind of humming or sizzling.
I instantly pulled out the USB and plugged it in again, but the sound
was there again, so I pulled out USB again. Then I noticed that there
was no battery inserted. When I inserted the battery everything was
normal, even when I plugged in USB. So there was no damage to the
neo1973. I also think the neo was smelling a bit after making that
strange noise, which was not really loud but disturbing. But maybe the
smell was an illusion because till then I never took a smell at the NEO
before.

<total_speculation> I hat the feeling the sound came from the vibrator
because it sounded like a motor not getting enough power to
move.</total_speculation>

I don't want to try further and maybe harming my device, but I hope you
can make something of it.
Should I file a bug report?

Regards
Patrick