Again... consider a few really important details: 1) there's evidence that Republicans and Indies voted in the Dem. primary for whatever reason and they voted for Bernie... 2) the polls stopped around Saturday before the Tuesday voting and missed a move... 3) a good deal of Bernie's support has been in spirit and never entirely serious - not talking about the people at his rallies but instead about people voting for a message... it's clear now that we don't need anymore shenanigans in this election with how far Trump has gone. It's time to vote with your head... 4) Michigan is much more liberal than Ohio in the rural counties and the pollsters probably updated their models in the past week, thus the tightening of the polls in Ohio...
If anything, this show the much more likely reality that Michigan was a one-off event and the polls two weeks ago for Ohio, Illinois and Florida were more or less on target.