Haven't done Cut-e at L3 but have done it with another airline. The behaviour of the controls in the complex control test that you've described sounds exactly the same as when I did it. Be careful of learning from the practice tests as although they emulate the real tests there are small details such as the behaviour in this test which they don't accurately replicate. Unfortunately I don't think there was anything wrong with your controls on the day, the test is just set up like that.
A good tip that someone gave me is to try the examples out a few times beforehand to get the hang of it before trying the real thing.
I believe that you have to pass all elements of the test to pass the whole assessment so even if you've done really well on the other tests, if you fail one element then you fail the whole assessment.