Map of google maps turns gray, but when I change the browser zoom back, what should I do?

So, guys, I have 2 parts of the system where I work, where I use a map to show the address of the property or person. But that in the property works perfectly, but in person (q has the same codes) I have to zoom in on the browser that looks perfect again .... Does anyone know what can happen to this? Thanks!

One important thing I forgot to mention, it's in a partialView, so it's being placed there while the page loads ...

Remembering that this code already existed in the system I just solved some problems.

    -edit-3
    var map;
    var marker;
    /* ============================ MÉTODOS PARA O MAPA ============================ */
    function initializeMap() {
        latlng = new google.maps.LatLng(-15.796892001990338, -47.890573438861864);
        var myOptions = { 
            zoom: 14, 
            center: latlng, 
            mapTypeId: google.maps.MapTypeId.ROADMAP 
        };

        map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
        createMarker(latlng);

        var position = undefined;
        <% var endereco = this.Model.Endereco;
        if (endereco.Latitude.HasValue && endereco.Longitude.HasValue)
        {%>
               position = new google.maps.LatLng(
               <%: endereco.Latitude.GetValueOrDefault().ToString(System.Globalization.CultureInfo.InvariantCulture) %>, 
               <%: endereco.Longitude.GetValueOrDefault().ToString(System.Globalization.CultureInfo.InvariantCulture) %>);
               changeMarkerPosition(position);
               <%}
        else
        {%>
        changeMarkerPositionByAddress(getEnderecoCompleto());
        <%}%>

        infowindow = new google.maps.InfoWindow();

        $("#mapaContato").css('display','block');
    }

    function createMarker(position) {
        map.setCenter(position);
        markerOptions = {
            draggable: true,
            map: map,
            position: position,
            visible: true
        };
        marker = new google.maps.Marker(markerOptions);
        google.maps.event.addListener(marker, 'position_changed', OnMarkerPositionChanged);
    }

    function changeMarkerPosition(position) {
        marker.setPosition(position);
        map.setCenter(position);
    }

    function changeMarkerPositionByAddress(address) {
        geocoder = new google.maps.Geocoder();
        geocoder.geocode({ 'address': address, region: "BR" }, function (results, status) {
            if (status == google.maps.GeocoderStatus.OK) {
                local = results[0].geometry.location;
                changeMarkerPosition(local);
            } else if (status == google.maps.GeocoderStatus.ZERO_RESULTS) {
                alert("Não foi localizada uma coordenada geográfica para este endereço.\nFavor localizar o ponto manualmente no mapa.");
            } else {
                alert("A busca no mapa resultou em um erro inesperado.\nErro: " + status);
            }
        });
    }

    function OnMarkerPositionChanged() {
        var local = marker.getPosition();
        updateMarkerPosition(local);
    }

    function updateMarkerPosition(latLng) {
        $("#Endereco_Latitude").val(doubleToString(latLng.lat()));
        $("#Endereco_Longitude").val(doubleToString(latLng.lng()));
    }

    function doubleToString(value) {
        <% var culture = System.Globalization.CultureInfo.CurrentCulture;
        var formatInfo = (System.Globalization.NumberFormatInfo)culture.GetFormat(typeof(System.Globalization.NumberFormatInfo));
        if (formatInfo.NumberDecimalSeparator == "," && formatInfo.NumberGroupSeparator == ".")
        {%>
               return value.toString().replace(".", ",");
               <%}
        else
        {%>
        return value.toString();
        <%}
    %>
    }