Checkboxes sometimes not being checked after .update()

I'm running into a strange bug where checkboxes which should appear checked in the editor window do not. When I close the editor window (changing nothing) and simply click "Edit" again the checkbox is now checked. Anyone else seen this before?

Example below. Notice that in the first screen the second checkbox is unchecked and after closing the Editor window and reopening the checkbox is now checked.

Here is the javascript which updates the checkbox:

function setNewsletterAds (newDate) {
    var date = moment(new Date(newDate)).format('YYYY-MM-DD');
    $.get("/modules/api/getNewsletterAds.php", {sid:$("#sid").val(), date:date}, function(d) {
        if (d[0].result == "success") {
            //console.log(d)
            var options = [];
            for ( i=1; i <= d[0].numads; i++ ) {
                options.push( { value: d[i].id, label: d[i].image_url} );
            }
            newslettereditor.field( 'newsletter_ads_available[].id' ).update( options );
            $.each($(".adCheckboxes").find(":input").next("label"), function() {
                $(this).html('<img src="'+$(this).text()+'">')
            });
            
            if (admin_level < 99) { //disable checking off ads if user is not a super admin
                $('.adCheckboxes .DTE_Field_InputControl input[type="checkbox"]').prop("disabled", "disabled");
            }
        } else {
            alert("There was an error loading the ads for this publish date. Please refresh the page and try again.")
        }
    }, "json" )
}

newslettereditor.field( 'newsletters.publish_date' ).input().on( 'change', function () {
    setNewsletterAds ($(this).val())
})

It works fine other than this strange "checked" bug.