Hi,
I know this was funny shape that administrative boundary is making, but this is taken directly from cadastre as open data and imported couple of years ago. We have today automatic maintenance and notification if adm. boundary is not correct. I fixed/reverted it already in https://www.openstreetmap.org/changeset/132786666. Adm. boundaries are already good, if you can - please don't change them:) Context: large discussion and import that took years to finish: https://forum.openstreetmap.org/viewtopic.php?id=68288