I have no idea why those other guys pit so early rather than using the tire.
Perez would have passed Ricciardo if he stayed out longer, he almost did just by staying out one extra lap let alone more.
Cars who react to the undercut without knowing it will work but also giving up their race strategy is just nuts. Every race it hurts people, Monaco, non passing tracks sure do it, tracks with great passing you want to optimise tire usage, being on slow tires at the end here by pitting to early is suicide. Was it 2011 where Ham gave up the lead with ~20 laps to go and passed Vettel/Alonso then was like 4 seconds a lap faster by the end.
5 second penalty for overtaking under a freaking safety car? Even though he was holding up Stroll for what a dozen laps or so, that is a massive net gain for Magnussen, ridiculous penalty. EDIT:- okay, they showed a replay and he gave it back, I thought it was for passing Stroll as they showed that replay earlier while talking about it.