To me it looks like there was an issue with a changeset https://www.openstreetmap.org/changeset/128477207 where the Rhone relation was somehow broken.

Additionally, it looks to me like this was fixed some days ago in https://www.openstreetmap.org/changeset/129117945

I presume it's only the rendering on OSM which has not caught up, as rendering water/large relations can take a while.