Solved

Not getting correct research pionts

The displayed percentage for research depends indeed on the combination of the TD and CD star ratings and CD strength yields a small bonus and the weakness hits the result quite noticeable. Race finishes play no role however, same for competition level except for how good that competition is in accumulating design points in their cars. 

The resulting DPs you get is directly the percentage as shown by the game applied to the gap of how much points your car is behind the car of the best team in that area (without Suppliers effects), always rounded up if the result is not a full number. So 50% and for example the best team has 87dp and you have 78dp and thus the gap is 9 points then 50% is 4.5, which is rounded up and results in 5 points. With a 10 point gap it's 5 straight, no rounding and thus 5 points again. With 11 it's 5.5 and thus 6 points.

So it doesn't looks like a bug, also there are no other reports and some managers in competitive leagues calculate and plan their research to the point and if the game would throw them an error I'm quite sure we'd hear about it soon. That huge gap is just too general a term and can easily yield both those results, to pinpoint a wrong result the exact amount for the gap is needed.