The JMC (only one where Jones had a supposed lead) over-sampled women by 6% (56% women polled to 44% men).
http://www.freerepublic.com/focus/f-news/3604152/posts
Vanity) Moore Leads in 5 of 7 Post Taken Since WaPo Story Broke
JMC has been around for a mere seven years. Something founded during the Obama years has very sketchy credibility IMO.
There you go and probably more error and failures that are publicly not known.
All throughout the presidential election in about every poll that we could see the internals, there were always something skewed, contradictory, or in error. The polls were in error so much that the pollsters either lied to themselves and everyone or they were plain dumb. Why is that? Because liberals mostly do polling and their error level went even higher because they didn't like Trump. Roy Moore is now the target of their hostility.