The Robot Operating System (ROS) relies on a centralized dependency index, rosdistro \emph{central index}, to manage packages across its heterogeneous software ecosystem, which integrates independently evolving Operating System (OS) repositories for system libraries, ROS repositories for domain-specific support, and Programming Language (PL) repositories for functional modules. While this design enables portability, it introduces a critical fragility since the entire ROS dependency management depends on this manually curated, static index that must map packages across independently evolving, multi-source repositories. This leads to persistent defects in the central index, such as missing, incorrect, or outdated installation rules, which undermine the reliability of ROS dependency management. To address this problem, we conducted the first in-depth empirical study of 863 real-world maintenance cases for the ROS central index. We categorize defects into coverage and correctness types, identify their root structural causes, and demonstrate that manual maintenance is bottlenecked by the difficulty of identifying equivalent packages across repositories. Motivated by these findings, we propose RosdepAuditor, an automated auditing framework that introduces a cross-repository mapping mechanism with hybrid scoring to infer package equivalence and detect defects. Evaluated on a ground-truth dataset, RosdepAuditor achieves 95.2% mapping accuracy without generating non-existent packages, outperforming existing pattern-based and upstream-based approaches, and leading LLM models. When applied to the live index, it uncovered 3,062 potential defects across 2,121 entries, 46 of which have been verified and fixed, demonstrating its practical usefulness in strengthening ROS dependency management.