Hi, thank you for your feedback. I've been dealing with some mega-polygon like this one for days, trying to narrow them down into pieces. That's still a work in progress. So that's understandable that I have made mistakes. For that, I apologise. I've fixed the issues for now (cf. https://www.openstreetmap.org/changeset/152911604), and will continue to work on this relation in the upcoming days.
Thanks for your vigilance, regards