When running the createIndexes command, if the requested indexes are already in the process of being built then the command will join on that existing index build. However, it appears that this is determined solely by the index specs without regard to the provided commit quorum setting. This means that if the already-running index build was started with a different commit quorum setting, the subsequent joining command will effectively use the commit quorum setting of that build. Thus its commit quroum setting will not be respected. Additionally, the command reply's commitQuorum field will be inaccurately populated with the commit quorum value provided to the command, not the commit quorum that was actually used.