Reproduction steps:
- Create a new map-reduce job, go to input data > query. Create a query with an ISODate, such as {datetime:{$lt:ISODate("2015-11-01T00:00:00.000+0000")}}
- Run the query (show filtered output data button). Create it so that it will return results.
- Save the job
- Load the job
- Go to input data tab. You will see your ISODate back like {"$symbol":"ISODate(\"2015-11-01T00:00:00.000+0000\")"}
- Run the query (show filtered output data button). It will not return results.

Why does it convert the ISODate to a symbol, when that breaks the query?