transform.localscale not working after update

Hello

I have a script for my enemy AI which flips the object and applies velocity to it (moves it left or right) when it hits an obstacle. I recently updated Unity to the newest version, before the update this worked like a dream but now on hitting the obstacle the AI turns correctly but continues in his previous direction anyway. I'm very confused as I have changed absolutely nothing. If anyone can see any mistakes I may have made or anything I would be very appreciative, I'm at my wits end right now.

Here is the method for turning the AI

 void turn(float prevDirection, float newDirection)
     {
         if (walkingDirection == prevDirection)
         {
             walkingDirection = newDirection;
             transform.localScale = new Vector3(transform.localScale.x * -1, transform.localScale.y, 1);
             if (walkingDirection == 1)
             {
                 isFacingRight = true;
             }
             else if (walkingDirection == -1)
             {
                 isFacingRight = false;
             }
         }
     }

here is the method for applying the movement to the AI

     void Move(float speed)
     {
         velocity.x = speed * Time.deltaTime;
         velocity.y += gravity * Time.deltaTime;
         controller.Move(walkingDirection * velocity * Time.deltaTime);
     }

and finally the if statement (in the update method) where these are applied:

         if(!alert && !caution)
         {
             spr.color = Color.blue;
             Move(100);
             positionSet = false;
             alertCoolDown = 1;
 
             if (controller.collisions.right)
             {
                 turn(1, -1);
             }
             else if (controller.collisions.left)
             {
                 turn(-1, 1);
             }
         }

I have included a .gif of the error in question so hopefully you can see what I mean: https://s21.postimg.org/tv7wcqyef/bug.gif

ANY help at all would be amazing. Thank you very much.