Update: This is how it now looks in Carto Standard: https://www.openstreetmap.org/relation/4218385#map=16/47.0232/12.4152
As noted, when the dark/light blue lines disappear in the OSM Inspector geofabrik view tonight all should be well.

Let me recommend JOSM to you since seeing u are on ID Editor. JOSM is very good at diagnosing problems on complex multipolygon to include the relations editor has a button to download all members, up to including very big and signal issues *prior* to saving the edit set with a validator pane listing all problems great and small. It's a bit getting used to, took me a while to learn all the tricks it knows, to include an easy function to combine side sharing areas of same and converting multipolygons to simple polygons with it's 'reconstruct' function.

Feel free to let me know if things are still not 100% here, but mostly, OSMI and Osmose notify the mapper(s) that edited an object i.e. I will be told automatically by the daily and 12 hourly diagnostic reports

ciao