I don't think its a case of a bug or bad design, its the way you drive this car along with a few of the other powerful MR cars like the 458, someone mentioned this in another thread here (sorry I can't remember who or where) but these cars need to be driven differently through the corners. You can't just thrown them into a corner like you can with the FR cars as the weight is thrown around differently and you'll spin out, you obviously need to brake sooner but if done correctly your exit speed will be much better than FR cars. The key trick mentioned by the other user was that these cars need at least some acceleration through the corner, you can't let off and let them roll through the corner like you can with the FR cars or you'll spin out like everyone is saying here. This technique has helped me immensely with these cars, I've gone from hating them to loving them.
They will be more suited to high speed flowing tracks and cars like the beetle, RSR and some of the FR cars will probably be more suited to technical, slower speed tracks with tighter turns. It used to be all the obvious choices in the top 10 times, the "instantly easy to drive" cars but I'm seeing a lot more 458's, 650's, R8's in the top 10 times these days and I think the Huracan will follow soon once more people figure it out. Yes they are harder cars to drive but that's the point because the reward is greater. Its the same with the McLaren, I saw a lot of them popping up in the top times so I started to work on my driving in that as it is the easiest MR car to drive for me, once I was getting consistent best times with the 650 I moved to the 458, once I got the hang of the 458 I was taking nearly 1 second off my lap times, I moved to the Huracan and shaved off another 0.5 seconds. The thing is this is still while having a few bad corners so there is still room for improvement with the Huracan, I bested every sector in it just not all in one lap, its a hard beast to tame but I believe if you can consistently you'll be up there with the best. I went back to my favourite cars to make sure it wasn't me just getting better at the track and my times went back up roughly 1.5 seconds. This was all done in Sport mode qualifying time trial with BOP and fixed settings.
I remember at the start of this game being so disappointed by the Huracan, 458 and some other MR's, they felt like I was driving on ice, I fell into the trap of thinking "oh well, a few bad laps, this car is crap" when really every car is supposed to have its strengths and weaknesses and its up to us to take the time to really figure them out instead of asking PD to make all the cars handle relatively the same. There needs to be a reward for those who put in the time and effort to master a car and I think the Huracan and 458 could possibly be it.