I find really strange that there are, at least according to this poll, so many people who would vote Biden (in a Trump/Biden matchup) but who would vote Trump when he is paired against another democrat, I mean you either like Trump or you hate him, there is no middle ground with him.
One thing I've noticed is in some polls there's very little difference between how different dems do vs Trump like CNN where the difference is only a few points and than there are polls like IBD where the difference is huge, double digit spreads. I guess it must be down to how different pollsters ask the question about H2H.