Object pulling to a perpendicular angle when on a slope

I'm trying to implement a kart racer in Unity and I've put down the steering and acceleration. I'm using a sphere as the kart for easier movement so I needed to code in a program snippet to align the kart model with the normal of the surface it is currently on. However, whenever my kart drives onto a slope, it starts pulling to either the left or right and stops at a right angle. The steeper the slope is, the harder the pulling force. I have no clue what is causing this. Here's my code for reference.

 public class KartController : MonoBehaviour
 {
 
     public float acceleration = 3f;
     public float brakeSpeed = 2f;
     public float steeringSpeed = 2f;
     public float KartAlignmentSpeed = 1f;
     public float gravity = 9.8f;
     public Transform KartModel;
     public Transform[] FrontWheels;
     public Transform[] BackWheels;
     public Transform SteeringWheel;
     public GameObject chassis;
     private GameObject sphere;
     private float speed;
     private float rotate;
     private float currentSpeed;
     private float currentRotate;
     void Start()
     {
         sphere = transform.Find("Collider").gameObject;
         speed = 0f;
     }
 
     void Update()
     {
 
         //Keep chassis at where the sphere collider is without rotating it
         chassis.transform.position = sphere.transform.position;
 
         //Inputs
 
         if(Input.GetKey(KeyCode.X))
             speed += acceleration;
 
         if(Input.GetAxis("Horizontal") != 0)
         {
             int dir = Input.GetAxis("Horizontal")>0?1:-1;
             float amount = Mathf.Abs(Input.GetAxis("Horizontal"));
             rotate = (steeringSpeed*dir)*amount;
         }
         
 
         currentSpeed = Mathf.SmoothStep(currentSpeed,speed,Time.deltaTime*12f);
         currentRotate = Mathf.Lerp(currentRotate,rotate,Time.deltaTime*4f);
 
         //Model
         KartModel.localEulerAngles = Vector3.Lerp(KartModel.localEulerAngles, new Vector3(0, 90 + (Input.GetAxis("Horizontal") * 15), KartModel.localEulerAngles.z), .2f);
 
         //Wheels
         foreach(Transform f in FrontWheels){
             f.localEulerAngles = new Vector3(0, (Input.GetAxis("Horizontal") * 15), f.localEulerAngles.z);
             f.localEulerAngles += new Vector3(0, 0, sphere.GetComponent<Rigidbody>().velocity.magnitude/2);
         }
         foreach(Transform b in BackWheels)
             b.localEulerAngles += new Vector3(0, 0, sphere.GetComponent<Rigidbody>().velocity.magnitude/2);
         
         //Steering wheel
         SteeringWheel.localEulerAngles = new Vector3(-25, 90, ((Input.GetAxis("Horizontal") * 45)));
 
         speed = 0f;
         rotate = 0f;    
     }
 
     void FixedUpdate()
     {
 
         sphere.GetComponent<Rigidbody>().AddForce(chassis.transform.forward*currentSpeed,ForceMode.Acceleration);
         sphere.GetComponent<Rigidbody>().AddForce(Vector3.down*gravity,ForceMode.Acceleration);
         sphere.transform.eulerAngles = Vector3.Lerp(chassis.transform.eulerAngles, new Vector3(0,chassis.transform.eulerAngles.y+currentRotate,0),Time.deltaTime*5f);
         
         //This piece of code aligns the chassis to the ground below it
         RaycastHit hit;
         Transform cT = chassis.transform;
 
         if(Physics.Raycast(cT.position,Vector3.down,out hit)){
             cT.up = Vector3.Lerp(cT.up,hit.normal,Time.deltaTime * KartAlignmentSpeed);
         }
         else{
             cT.up = Vector3.up;
         }
 
         cT.Rotate(0,sphere.transform.eulerAngles.y,0);
     }
 
 }

Edit:

I managed to find the issue that causes the kart to autopull to a hard 180 degree angle on slopes by changing line 50 of my code to

 sphere.transform.eulerAngles = Vector3.Lerp(sphere.transform.eulerAngles, new Vector3(0,sphere.transform.eulerAngles.y+currentRotate,0),Time.deltaTime*5f);

However a residual problem still remains and that is, when I turn the kart sharply enough, it's Y rotation starts 'flipping' between x and x+-180 every frame for some reason. I narrowed the bug down to the above line as well. Something seems to change in the Lerp function. How would I fix this without bringing back the original issue?