System: V+12 voltage in enclosure Internal is out of spec.

A droop in power brick's input power will not normally cause the output of the power brick to droop.  If it drooped far enough, it could shut down, but that would have re-booted your NAS.  If the connection to the NAS is loose, that could be an issue, but it would most likely need to be wiggled for the droop to occur.  A temporary high demand on the 12V power, like a failing hard drive, might cause a droop in the 12V.  Just because there are some for whom the typical fix did not work is not really a good reason not to try it, IMHO.  What matters is whether the investment in a replacement supply (12V, 5A with a  5.5mm x 2.5mm or 5.5mm x 2.1mm connector) is worth it to you if it doesn't work.  Given there are a coupe on Amazon right now for <$10 (assuming you are in the USA), it's not a bad investment for what is very likely to be the fix (again, IMHO).  I suspect you can find far more "yes, it was the power brick" responses to similar questions than ones where it was not.  But unfortunately, some for whom a fix we recommended works never come back to confirm it was.  But they do if it didn't fix it, because they want another option.  

Of course, with it not currently showing the error, it's not going to be obvious if you just saw an unusual glitch or if the replacement was necessary.  Then again, if that is the problem and you don't replace it, a future failure could corrupt your volume.