Hey Chenio. Thanks for your report on this. You may want to [url=https://www.bungie.net/en/Help/Article/12539]clear your console cache[/url] and check to see if that might help with your issue, then try again.
Have you completed the quest to get the Izanagi’s Burden? I am not 100% sure but I believe the triumph is completed once you do that as you get the Obsidian Accelerator from Ada at the end. You can get them from the forge but they may not count towards that triumph.