The greatest segregation of duties conflict would occur if the individual who performs the related tasks also has approval authority for purchase requisitions and purchase orders. This is because these two tasks are directly related to each other and involve financial transactions. If the same person is responsible for both tasks, it could lead to potential fraud or error12. For instance, the individual could approve a purchase order for a personal need and then also approve the payment for it, leading to misuse of company funds12.
References:
Segregation of Duties: Examples of Roles, Duties & Violations - Pathlock Functions in the Purchasing Process and how to Segregate Purchasing Duties