U2720Q: Design or QC issues?

I bought two U2720Qs around last Christmas for home office use.  Both have exhibited a backlight issue: One backlight, usually the far right one, would go dark during normal usage, every few hours to days; power cycling restores the backlight.  I went through 3 replacement monitors so far, 2 of which had the same backlight issue, and now I'm about to go through the 4th replacement.

I wonder if this model has been plagued with bad batches or maybe even a bad design; I hope this 6th monitor (4th replacement) would be a good one.  (Based upon my experience there's a 20% chance :-p.)