PPP IS such an arm of the Democrat Party, that I pay little attention to them till the September before a November election. By September they understand their credibility is on the line.
Below is an article setting out the polls in the Cotton Pryor race in 2014. You will notice that PPP’s numbers do not get in line with the other polls until September. ALWAYS REMEMBER PPP IS FIRST AND ALWAYS A DEMOCRAT POLLSTER.
https://en.m.wikipedia.org/wiki/United_States_Senate_election_in_Arkansas,_2014
PPP is no more a "evul Democrat pollster" than, say, your beloved Reuters or Rasmussen are "Republican pollsters".
Anyway, this looks like the final margin, give or take a couple points.
This Wikipedia article describes the firm as a Democrat firm:
https://en.m.wikipedia.org/wiki/Public_Policy_Polling
I do not think they are evil. I do tend to ignore them till September. But I always agree they should be in the RCP AVERAGE.
PPP's founder is a Democrat, but they are no more an arm of the Democratic Party than Rasmussen etc. are of the Republican Party. PPP has a historically good track record; 538's database gives them a B rating with a slight D lean (+0.3) based on over 400 polls .
If you throw out PPP, you need to throw out Rasmussen etc. as well. Or Fox News, a conservative organization whose polling is also quite good.