The Movie Database Support

Hi,

I have a problem when I get the movies list now playing one time I have the movie between 2018-06-10 and 2018-04-20 and a second time, I have the movie liste between 2018-06-03 and 2018-04-16. I don't understand why ? I execute always the same request: https://api.themoviedb.org/3/movie/now_playing?region=CH&page=1&language=fr-CH&api_key={api}

There is the dates object results:

[dates] => stdClass Object
    (
        [maximum] => 2018-06-10
        [minimum] => 2018-04-20
    )

[dates] => stdClass Object
    (
        [maximum] => 2018-06-03
        [minimum] => 2018-04-16
    )

Thanks for your help