Well I guess it's 100% firmware related as just to be sure I swapped devices and the second one just did the exact thing same. I guess my USB controller/drive via NTFS isn't supported and it's not handled gracefully. I'd try ext3/4 but since I have the NV+ v2 I can't format the drive via the NAS and I currently don't have any other way. I might try another enclosure and or the USB 2.0 port and see what happens...
Just noticed the NAS display says: Volume C: Life Support
Once I unplugged/plugged everything came up fine.
I'm attempting the same backup via the front USB port now. I do have a question... When transferring data to a attached USB port is the data is being sent over the network versus directly to the USB port? If so, I guess my router could come into play (although with the NV+ v2 saying Life Support I doubt it)... having difficulties transfer that much data (from and to). I did note that when it went offline holding the power button down for 20 seconds it didn't power down. Not sure if it should have or not. Anyway I've love to know which log files to see/check to find out what is actually happening.
I tried a call into support and it was worthless. I spent about 99% of time trying to convince them what model I have... even after giving them the serial number. What colors is your NAS?

It doesn't have v2 on the back so it isn't... even though it's printed on the front. Then they stated my drive isn't support which it clearly is. Before I got too upset I got smart and simply asked can you analysis why it's going offline and he stated no. Then thanks for your patience I'm hanging up.