"Never attribute to malice that which can be adequately explained by stupidity"ok maybe hyperbole from me but surely Bernie would have edged it at the least. There was back dealings going on for the 2016 race. It makes sense. Money and big business run the show and Bernie is a thorn in the side off all that and his passed make them know he’s the real deal and can’t be bought.
Caucuses are probably more vulnerable to shady dealing than primaries - or to put a positive spin on it "enthusiastic supporters influencing others". However in 2016 Sanders did much better in caucus states than he did in ones with just direct voting so it seems odd to claim that there were caucus back dealings that overall negatively affected him.
Caucuses do self select for a strange demographics - those with say two jobs can rarely spare the time which probably disadvantages him but on the other hand students seem to be slightly over-represented so think it is swings and roundabouts tbh.