A few brighter spots for Menendez, the poll is only 8% black, but NJ electorate is around 14% black, and asians are less than 1% of the poll, but are over 8% of NJ and a little under that in the electorate. Menendez is probably leading by 5-6.
According to exit polls from past off-year elections in NJ, African-American's have been about 10% of the electorate (looking back at 2006 and 2017), and not 14% which is the presidential level. Same thing for Asians, they have consistently been about 3% of the electorate in past off-year elections, so this poll isn't that far off. But who knows, that could all change.