Berlin isn't centralized, but the districts (Bezirke) have quite some freedom to structure their work (similar to "kommunale Selbstverwaltung" in other states) and how they run the administration offices (Bürgerämter etc.) which then leads to city administration passing a law for something and each district implementing it differently and city administration having no authority to override district decisions, while taking the blame.
Fixing this requires a change to the constitution, but that requires a 2/3 majority in the city assembly (Abgeordnetenhaus) or a referendum. Getting the majority is hard as there are varying differences (from parties being happy about number of posts to full, like district mayors etc.) and "dislike" between districts (East/West, center/outer, ..)