Problem with wave like movement when rotating around X and Y axis with mouse input // Please Close/Delete

Please close and delete this question, as I fixed all the issues in another question. It would not make sense to edit this question, due to the number of changes I made. Link to the other:
Unity Answers Link

We would need more info on the project setup, in order to properly answer the question.

What is the value of moveSpeed? Is it constant? Does it change?
Is headWithCamera hierarchically linked to this GameObject?
When is the moveView function called?