The intel team is parsing structured mongodb logs for a variety of tools. The slow logs contain customer's query patterns and when there is a slow log it is assumed that the query was successful. We have identified a spike of parsing failures (in the Java driver) related to $date expressions that are not necessarily formatted as a valid operator value but are still valid to be executed on mongodb. Here are the examples we have run into

Example 1: $date is not followed by a closing }

"fieldName":{"$date":1740473993720,"$update":1740473993720, ... 

JSON reader expected token type 'END_OBJECT' but found ','.
org.bson.json.JsonParseException: 
	at org.bson.json.JsonReader.verifyToken(JsonReader.java:518)

Example 2: $date is followed by another $date - while technically not correct it is a valid expression as $date could be considered a field name

{"$date":{"$date":"2025-02-25T09:00:26.829Z"}} 

Example 3: The date/time has an invalid format but we are also getting a parsing exception here - should this just be considered a string/object?

{"t":{"$date":"2023-08-21T23:11:52.687334"},"_id: {"$oid":"67aba15bcdd5233e492a3a55"}}