I'm trying to query documents with a date lesser than or equal to a given query date.

Here's the query as written in a Spring Data repository (Java):

{ 
    'subscriptionPeriodStart': { $lte: ?0 }, 
    'nStickers': { $gt: 0 }, 
    'status': { $nin: [ 'Canceled', 'Refunded' ] } 
}

"?0" being the first parameter passed to the repository's method, of type java.util.Date.

The query is translated by the driver into this query:

db.bill.find({ 
 "subscriptionPeriodStart" : { "$lte" : 1608422400000},
 "nStickers" : { "$gt" : 0}, 
 "status" : { "$nin" : [ "Canceled", "Refunded" ] }
})

The result of the query is on screenshot "screen 2". No documents are returned.

I rewrote the same query using another syntax:

db.bill.find({ 
 "subscriptionPeriodStart" : { "$lte" : ISODate("2020-12-20T00:00:00.000Z")},
 "nStickers" : { "$gt" : 0}, 
 "status" : { "$nin" : [ "Canceled", "Refunded" ] } 
})

And the documents are returned (screenshot "screen 2").

Is this a bug or a feature?

Environment:

• MongoDB: v3.6.17
• Java driver: org.mongodb/mongo-java-driver v3.11.2
• Spring Data: org.springframework.data/spring-data-mongodb v2.2.4.RELEASE
• Java JDK v1.8.0_261

Thanks!