Hi Thomas

Everything is fine with your code, can you show all your view?

I tried excluding some code; which fixed the issue where the /source for each source was added.

<section class="article-list">
    <h2 class="screen-reader-only">Artikler</h2>
    @Html.Partial("_ArticleList")
</section>

This is the code for the view:

@using Project.Web.classes
@inherits Umbraco.Web.Mvc.UmbracoTemplatePage
@{
    var newsPool = Model.Content.AncestorOrSelf(1).Url + "aktuelt";
    var currentSite = Model.Content.AncestorOrSelf(1).Name;
    var articleList = Umbraco.TypedContentAtRoot().First().Descendants()
                .OrderByDescending(x => x.GetPropertyValue("artikkelDato")).Where(x =>
                x.DocumentTypeAlias == "newsArticle" &&
                x.GetPropertyValue<IEnumerable<string>>("publiserTil").Contains(currentSite) &&
                x.GetPropertyValue<bool>("synligPaaHovedsiden") == true)
                .Take(6);
}
<div class="article-inner row">
    @{ 
        var i = 0;
        foreach (var item in articleList)
        {
            var img = item.GetPropertyValue<IPublishedContent>("artikkelBilde");
            var imgLarge = img.GetResponsiveImageUrl(450, 270) + "&mode=crop";
            var imgMobile = img.GetResponsiveImageUrl(296, 185) + "&mode=crop";
            var articleThumb = imgLarge;
            if (Helper.IsMobileDetect())
            {
                articleThumb = imgMobile;
            }
            var excerpt = item.GetPropertyValue<IPublishedContent>("artikkelInnhold");
            i++;
            if(i == 4)
            {
                @Html.Partial("_Ads", new ViewDataDictionary { { "adSize", "small" } })
            }
        <article class="news-card col-lg-4 col-sm-4 col-xs-12">
            <div class="img-container">
                <a href="@string.Format(@"{0}/{1}", newsPool, item.UrlName)" title="@item.Name - Les mer">
                    <img src="@articleThumb" alt="@img.Name" class="img-responsive" />
                    <div class="img-overlay"></div>
                </a>
            </div>
            <div class="text-container">
                <h3>@item.GetPropertyValue("artikkelTittel")</h3>
                <p>@Helper.Truncate(item.GetPropertyValue<string>("artikkelLead"), 125)</p>
                <a href="@string.Format(@"{0}/{1}", newsPool, item.UrlName)" title="@item.Name - Les mer" class="read-more">Les mer</a>
            </div>
        </article>
        }
    }
</div>

So stripped the view down to this:

@inherits Umbraco.Web.Mvc.UmbracoTemplatePage
@{
    Layout = "Master.cshtml";
}
@if (Model.Content.HasValue("frontPageCoverMedia"))
{
    var coverMedia = Model.Content.GetPropertyValue<IEnumerable<IPublishedContent>>("frontPageCoverMedia");

    <video id="frontCoverVideo" width="1920" height="450" autoplay loop muted controls>
        @foreach (var mediaItem in coverMedia)
        {
            var mediaType = "";
            var mediaUrl = mediaItem.Url.ToString();
            switch (mediaItem.GetPropertyValue<string>("umbracoExtension"))
            {
                case "mp4":
                    mediaType = "video/mp4";
                    break;
                case "webm":
                    mediaType = "video/webm";
                    break;
            }
            <source src="@mediaUrl" type="@mediaType">
        }
    </video>
}

<section class="article-list">
    <h2 class="screen-reader-only">Artikler</h2>
    @Html.Partial("_ArticleList")
</section>

This code still generates the error.

Did some more digging at it seems it all leads to these lines of code

var imgLarge = img.GetResponsiveImageUrl(450, 270) + "&mode=crop";
var imgMobile = img.GetResponsiveImageUrl(296, 185) + "&mode=crop";

As soon as I use the native GetCropUrl instead of the Slimsy one the closed source tags dissapear.

Further than that, I have no idea as to why this is happening.

is working on a reply...