Yes but they all come up with the same overall answer.
In my opinion, the reason the gap has steadied is that the reporting of the issues hasn't changed. Most of the biggest online news sites are strongly pro-leave and tailor their coverage accordingly. If your news diet was just the Sun, Mail, Express or Telegraph you wouldn't be reading about Johnson's consistent bungling and incompetence. You'd be reading about him standing up for the people against Parliament and the EU, and about the EU being disrespectful etc..
As posted a few pages ago, the total visits to news sites favours the Leave supporting ones by around 3 to 2 when compared to Remain ones (Guardian, Mirror etc.). That has got to make a difference.