Scaling an object causes slow movement (Since Update 5.5.4)

Any object with a rigidbody2D attached, which is moved using velocity, slows down whilst using transform.localScale to scale the object. The scaling code I use is:

transform.localScale = new Vector3(Mathf.Lerp(transform.localScale.x, 1, 5 * Time.deltaTime), Mathf.Lerp(transform.localScale.y, 1, 5 * Time.deltaTime), 1);

To clarify, this worked fine before I updated my unity version to 5.5.4. After I updated, the movement is slow and jerky.