There wont be a penalty, it's an odd incident, i can see it from both perspectives.
It was strange how Hamilton didn't just overtake him, I know he wasn't aware that Max had been told to slow down but he had plenty of time to react as the slowing down was very obvious and gradual to begin with, he could have easily just drove past him but instead he slowed down and matched Verstappens speed which possibly suggests some kind of tactics from both of them involving who gets the DRS (something Hamilton mentioned in his interview).
On the other hand why did Max slow down so much and for so long ? it looks from the replays that he stopped more abruptly once Hamilton was right behind him but without telemetry its hard to say. Verstappen fans will say why did Hamilton even get that close to his rear in the first place when he could have just driven straight past.
Unless the telemetry says otherwise im pretty certain it will slapped wrists for both at most.
A few reasons I think.
One, it's all happening pretty quick and it's plausible Hamilton simply couldn't comprehend what was happening in the moment.
Two, Verstappen is known for being aggressive - he was swinging the car right to left while slowing down, at a narrow part of the track. Hamilton, sensibly, would have second thoughts of being any part of that.
Three, if he suspected a brake check, which would have went through his mind instantly, he'd have been waiting for Verstappen to speed up again (which, by the way, Verstappen did - it wasn't a smooth slow down; he broke, then sped up, then broke again.)
It was, at the very last second, a sudden brake by Verstappen that caused the collision, as he went from easing off to basically slamming on, which I'm sure the telemetry will show as it's very visible with the naked eye.
