The Phoenix Police Department is the law enforcement agency responsible for the city of Phoenix, Arizona. Today , the Phoenix Police Department comprises more than 2,900 officers and more than 1,000 support personnel. The department serves a population of more than 1.6 million and patrol almost 516 sqmi of the sixth largest city in the United States.
The Phoenix Police Department has 3,901 employees
The police department "comprises MORE THAN 2,900 officers and MORE THAN 1,000 support personnel.". The context does not specify an exact number, however the number given in my answer is plausible but not defined explicitly in the context. I believe the system was fooled as it may have tried to do the math and incorrectly assumed that a logical math statement based on available numerical data is equivalent to what the data needs to say in its grammatical context.