Cops tell you all kinds of stuff. Almost all the time it's because they are trying to get you to do something different then what they are telling you.
Bingo! For some reason, folks assume that cops are honor-bound to tell the truth, but as a practical matter, they can basically say anything.
The exact opposite is true for the average citizen. One LEO advised me, years ago, to never, ever, ask a cop for legal advice. As he put it, "An officer's job is to enforce the law, and if you make him aware of a violation, even while asking advice, he'll arrest you." It can therefore be hazardous to volunteer information of any kind to an LEO...