The serverStatus output section collected in "last pings" contains two keys named:

• lastPingData.serverStatus.metrics.commands.mapReduce
• lastPingData.serverStatus.metrics.commands.mapreduce

These two keys are within the "serverStatus" section of the document.

Names that only vary by case sensitivity is perfectly legal in BSON and JSON.
However, it causes issues for SQL tools that try to read the document. As a note, this issue was noticed while using Presto to query the dataset.

The first key contains:

                        "mapReduce": {
                            "total": 0,
                            "failed": 0
                        },
 

While the second key contains:

                        "mapreduce": {
                            "shardedfinish": {
                                "total": 0,
                                "failed": 0
                            }
                        },

Because this second key is the only command that uses this shape of using a "shardedfinish" sub-object, we could replace it by something like:

                        "mapreduce_shardedfinish": {
                            "total": 0,
                            "failed": 0
                        },
 

The above is one suggestion.
The request is to have names that differ for more than their case for the two keys.