There isn't enough info in your post to help you answer question 1. Most likely cause is the same as in your link: user error with whomever setup the array.

2- Not very likely; The rebuild would have overwrote every sector when it created the array on V: if it wasn't already part of it. You could run a deepscan and see what you get. Plan on that taking a day by itself.


I'm with popatim here. Some kind of user error in the settings is the most likely scenario, but we don't know much about your setup at all. Yes, the link had something with similar symptoms, but there are a lot of causes, so you can't just point to something and say "that's the identical problem."

Fixing it at this point is going to be problematic. It'll be far better to simply recover from your backups and start the RAID over. Or better yet, not use one at all; they're objectively poor ideas for the 99% of consumers who don't fit the very specific things RAID is good at (professional use of very large sequential files, servers/storefronts that care more about being online than data integrity, etc).