Helmet shouldn't come off like that if it was properly attached, Spikes didn't lead with his helmet, contact was incidental. It looks like the helmet only came off when he impacts the ground, I don't think it's a dirty hit but that gets called in todays NFL. The hit on Jackson was the furthest thing from dirty, Jackson put his head down to try for extra yards and got stonewalled, looked like we had that fumble recovery too. As for the alleged taunting, I think his arm might have been bothering him so he was checking it out, if that was flexing that's pretty weak.