If a thread doing removeShard on the config server calls shardRegistry->getShard() in order to check for the existence of a shard, it may not see that the shard has already been removed by another thread. If instead of getShard() we perform a local read + wait for majority write concern, if a concurrent remove is happening but not yet replicated, we will correctly error out. Repro is attached for test configsvr_metadata_commands_require_majority_write_concern.js.