I have been using and testing this same model for almost a month now and I have not seen this issue and has been working just fine for me.
Please make sure you have all drivers up to date including BIOS. You can also try running all windows updates.
I have all latest BIOS and driver installed in my system. Any log or tools you could suggest so I could trace down what exactly the system was done with those notification?
We do not have any software with these characteristics but please check the other USB connections.
What happens if you connect other USB Mouse and Keyword? Have tested theses components in other systems?
Perhaps the USB is faulty so you can also contact our support center:
hey Kevin, I suspect it is not relate to USB issue but some "hardware" or "driver" issue causing the notification sound. My keyboard and mouse keep working very well, whatever on my NUC or my desktop, there are no "USB notification icon" in my system tray before and after the notification sound. And you know, that notification is share the same across with all "hardware removal" or "hardware change cause by driver" .....
From my end, I’ve been using this same model as you are and haven’t been able to replicate this behavior. What I’d suggest you to do is to try to do a fresh install of the Operating System. If this doesn’t solve the problem either, please contact us at our technical support center: http://www.intel.com/p/en_US/support/contactsupport