Exit polling is too easy to skew by the team conducting the polling.
There are two excellent examples from prior elections cited in a report at the link below.
In the 2004 presidential election, skewed exit polls in Virginia were used by Democrats to influence voters in western states where polls were still open. Undecided voters sometimes vote for the candidate that appears to be winning. It’s the the old ‘get on the bandwagon’ syndrome.
Virginia exit polling in 2004 showed the state tilting heavily for John Kerry but the polling was purposely rigged. Virginia went for George W. Bush.
The report at the link below also cites the purposely flawed exit polling by Democrats in the state of Wisconsin in 2012.