Hi mynameisjonas,

Thank you for your contribution to openstreetmap.  By removing way 1348687617 from the relation 16875921 it has made that multi-polygon winter sports area invalid as the border is no longer closed.  The iD editor should give a hint there when this happens. You can also see this error in some of the popular QA tools including:
https://osmose.openstreetmap.fr/en/map/#loc=13/46.01413/-68.71308&item=xxxx&level=1%2C2%2C3&issue_uuid=546f3d4f-30c3-82c0-3ec5-5cc162c6c576

https://tools.geofabrik.de/osmi/?view=areas&lon=-68.62614&lat=46.08290&zoom=11&baselayer=Geofabrik%20Standard&overlays=duplicate_node%2Csingle_node_in_way%2Cduplicate_segment%2Cway_in_multiple_rings%2Cintersection%2Cintersecting_segments%2Cring_not_closed%2Ctouching_rings%2Crole_should_be_inner%2Crole_should_be_outer%2Cinner_with_same_tags%2Cways%2Cduplicate_node%2Csingle_node_in_way%2Cduplicate_segment%2Cway_in_multiple_rings%2Cintersection%2Cintersecting_segments%2Cring_not_closed%2Ctouching_rings%2Crole_should_be_inner%2Crole_should_be_outer%2Cinner_with_same_tags%2Cways

Cheers,
scarapella