I highly doubt the barrel warped, I used, shot and sold thousands of these things, as well as used a lot in full auto(actually did a drill to see how many rounds on full auto it took to MELT a barrel to make it bend in full auto mode)

I have never seen anyone warp a barrel, I have however seen many guys shoot the rifling out of barrels shooting them too hot in a LOT of fast reloads and long non stop firing (more so in full auto's)
IMO< I will guess, it might just be the shooter, NOT all AR's of the same quality on trigger pull, making some folks that normally shoot better shoot worse!

and like all things, all the more so with SO many company's making and selling AR type rifle parts, and folks BUILDING and mix matching parts, its not that un common for things to be OFF a LOT, pending production runs, quality of part period, and who put things together!

way too many variable's here to Claim a warped barrel IMO

BUT anything can be possible too I am sure
just its a VERY low odds deal IMO!
been in the shooting game a LONG time!