Ok i may have found the culprit...

this 

[Task("D2161E9B-FDF6-4F8E-8595-794B10A488F4", TaskTriggers.Hive.Revisions.PostAddOrUpdate, ContinueOnFailure = false)]
    public class OnSaveAndPublish : AbstractTask
    {
        public OnSaveAndPublish(IFrameworkContext context) : base(context)
        {
        }

        public override void Execute(TaskExecutionContext context)
        {
            var umbracoContext = Application.GetApplicationContext();
            var hive = umbracoContext.Hive.Cms();
            var backOfficeRequestContext = Application.GetBackOfficeRequestContext();
            var hContext = HttpContext.Current;

            foreach (var hostname in backOfficeRequestContext.RoutingEngine.DomainList)
            {
                //ToDo: Iterate and generate new sitemap depending on lang then save it to file.
                Content rootContent = hive.Content.GetById(hostname.ContentId);

                var siteMapBuilder = new SiteMapBuilder(hostname.Hostname, rootContent);

                string path = rootContent.Name;

                if(rootContent.Attributes.Contains("sitemapFilename"))
                {
                    var sitemapFilename = rootContent.Attributes["sitemapFilename"].DynamicValue;

                    if(!string.IsNullOrEmpty(sitemapFilename))
                    {
                        path = sitemapFilename;
                    }
                }

                path = hContext.Server.MapPath("~/") + path + ".xml";

                using (var writer = new XmlTextWriter(path, new UTF8Encoding(false)))
                {
                    writer.Formatting = Formatting.Indented;
                    siteMapBuilder.SiteMap.Save(writer);
                }
            }
        }
    }

somehow this prevents the publish but i have not canceled the event ore anyting... unkown bugg in the event or someting dident go as planed.

Edit:

changed

TaskTriggers.Hive.Revisions.PostAddOrUpdate To TaskTriggers.Hive.Revisions.PostAddOrUpdateOnUnitComplete

Now it works :)