I have an issue with a list of tags used on a multi culture website where the simplified cshtml below returns 0.

@inherits Umbraco.Web.Mvc.UmbracoViewPage
@using ContentModels = Umbraco.Web.PublishedModels;
@{
    Layout = "System.cshtml";
    var allTags = Umbraco.TagQuery.GetAllContentTags();
    var allTagsCount = allTags.Count();
    <p>@allTagsCount different tags are used on the site</p>
}

The snippet works just fine on other single culture websites and yes, I am sure that the site has more than 0 tags :-)

What am I missing?