To fix self intersecting lines:

https://tools.geofabrik.de/osmi/?view=geometry&lon=4.46033&lat=50.43393&zoom=15&baselayer=Geofabrik%20Standard&overlays=self_intersection_ways%2Cself_intersection_points%2Csingle_node_in_way%2Cduplicate_node_in_way

Kind regards
Guido