OK, https://www.openstreetmap.org/relation/14510149 is a valid relation again.  https://overpass-turbo.eu/s/1V39 will show the relation at this point in time.  Your version, which had all the duplication in it, was https://overpass-turbo.eu/s/1V38 .  I'd expect that you'll want to add existing ways to the relation to do that, but you'll need to make sure that you don't duplicate any geometry of the current relation, which will break it as a multipolygon.
