One of two things is happening here: either this guy has an incredibly defective gun, or he's using a cheap airsoft or bb gun to get attention and get views on his youtube videos. I suspect the latter, because his dialogue is very inconsistent ("haven't even shot this FN today" ... "noticed the issue when mags wouldn't drop free") and, well, a defect of this level is about on par with discovering that the steel and aluminum chassis of your car was actually made from plaster and papier-mache.
This google search will show you discussions about magwell flex within the last week. All of them are this video popping up on different gun sites. In basically every topic several people immediately put their FNs out in the 100 degree sun to see what happens, and report a bit of flex but only a small fraction of what the video shows.
This google search will show you discussions about magwell flex within the last week. All of them are this video popping up on different gun sites. In basically every topic several people immediately put their FNs out in the 100 degree sun to see what happens, and report a bit of flex but only a small fraction of what the video shows.