What is the qb contain glitch

It's the same/similar issue that has been in Madden for years. Left handed QBs can't really do it as well (only to one side) but you can basically get a speed boost, giving you instant control over your QB to roll out from the pocket. Works better on certain plays than others, but is possible both from shotgun and under center formations.

It's really nasty to defend against, because you can easily scramble for huge gains, or throw on the run and hit nearly any corner, post, drag, curl routes or whatever you prefer to set up.

I'm not great at nailing perfect blue passes while on the run, but if even my dumbass can learn it in 15 minutes, basically anyone can do it. Well, almost. There's some real clowns around here, constantly licking EA's boot.