They’re including 3rd party candidates in most polls, even though they will never get more than 1% of the vote, and they keep oversampling Dems by 10+% even though Republican turnout has been much higher than Dem throughout the entire primary.
The polls are wishful thinking.
They always over-sample the Democrats, because they have more registered voters. There is a problem in that though.
The Democrats will register anyone on two wheels. (Every person they can con into it by reasoning, pleading, or threatening ...)
These folks are not nearly as motivated as people who register as Republicans, because they mostly do so of their own volition. They find out how to do it. They go out of their way to do it. And they go out of their way to make it to the polls and vote.