Hi. So I have a 2018 Crosstrek and a few weeks ago I had my Subtle Solution 1.5” kit installed. Since the install I’ve had a creaking noise coming from the rear passenger side. The sound usually happens when I accelerate from a dead stop and at low speeds. I have brought to the shop that did the install numerous times and still the creaking continues. When I shake or jump on the the car you don’t hear anything. It seems to happen when the vehicle is in movement. The shop already dissembled and reinstalled the kit and it still continues. The springs was never compressed or removed and it's only coming from the rear passenger side. The sound is like something is flexing to the point of a creak and kind of a movement of a bolt but I have been reassured that everything has been tightened down. It’s super hard to explain. But PLEASE HELP. Any suggestions would be greatly appreciated. This is my first Subaru. Thanks.