Though the polls in early May showing a deadlock were far more representative of the actual results than the blowout shown at the end.
National polls are never very useful since they can change extremely quickly after the early primaries, but they become completely useless after a large chunk of states have voted since it's impossible to distinguish between a) people genuinely changing their mind b) them just having an unrepresentative sample of people who may not even have voted and c) bandwagoners.
However, this one doesn't look too off. I don't really feel like going through the effort of the math on this, but if Bernie performs very well on June 7th it might be possible to get the PV to within single digits.