Large string stored as ### in a field of a document

This is in a MEAN app. I have a field of type string in one of the Models.

const sebiListSchema = mongoose.Schema({
  .....
  orderDetail: {type: String},
  .....
})

const SebiList = mongoose.model('SebiList', sebiListSchema);

module.exports = { sebiListSchema, SebiList }

When the data is uploaded in the collection(using a csv file upload), any string data that is large, e.g. 7000+ characters, gets stored as ‘######################’ in mongoDb. Pls refer to attached image. Why is this happening?