Two types of voters can account for the early exit poll discrepancy in NY.

First, absentee voters were not included in the exit polls. Absentee voters are usually older voters and older voters strongly preferred Hillary.

Second, the voters who voted on provisional ballots. Provisional votes would only be counted if the voter turned out to be a registered Democrat. Independents were being encouraged to vote with provisional ballots, in case an emergency lawsuit resulted in an opened primary; and up to 20% of those exit polled said they were Independents. Since the injunction wasn't granted, the votes of non-Democrats would not be counted.

So the absentee votes, which favored Hillary, were not included in the exit polls; but the votes of Independents, which favored Bernie, were.

The 126,000 purged voters were not concentrated in neighborhoods known to have high support for Bernie, but spread throughout the borough, so they're less likely to be a factor.