All kinds of stuff messes up on the dyno. SO yes it could have been caused by the dyno, but it was going too happen eighter on the dyno or streets!!

2nd how do you know it didnt have back presure while on the streets? Do u have a camera under your hood. More then likely its your rings. read my comment above..

And if you didnt want them taking it too redline you should have stopped them. Eighter way those problems that just happened nothing u can do but fix them!!!!!