According to Nate Cohn who I don't think distorts the data, Trafalgar was the 7th most accurate pollster in 2018, beating Marist and Quinnipiac. It had a 1.87% error on average in favour of the GOP. By contrast, Fox had a 3.05% error in favour of the democrats, Marist had a 4.43% error in favour of the democrats and Quinnipiac had a 2.75% error in favour of the democrats, so Trafalgar's bias was within the normal range.
twitter.com/GravisMarketing/status/1067057315327692805
I don't doubt that their last poll of the cycle will be fine, but this sample is trash. There is no universe where over 2/3rds of voters will be people over 50 and only three percent black.