If you’ll notice on this particular run play inside, up the middle, the HB runs up the mid and clearly breaks the first down plane, then winds up going the negative direction. I wonder why they did not award him the first down, since he clearly got to the first down marker! https://paydirt.myfootballnow.com/watch/3655#663237
I don't know why, but the RB goes backwards on his own, therefore is down where tackled. The forward progress rule does not apply here. This could possibly be a bug.