Mongo Transporter PipeLine Data MisMatch Issue

Question

I am using transporter pipeline to get sync my NoSQL DataBases between Source DataBase Mongo (Version=3.4) to Sinc Database Mongo (Version = 4.4).

Here I established the connection properly by having below configuration in Pipeline.js

var source = mongodb({ "uri": "mongodb://parentHost:27017/mongodb?authSource=admin"  "tail": true})

var sink = mongodb({"uri": "mongodb://childHostName:27017/mongodb"  "bulk": true});

t.Config({'write_timeout': '5000s'}).Source("source", source, "/^testing$/").Save("sink", sink, "/^testing$/");

After Setting Above Configuration for Source and Sync Databases I launched my Transporter Pipeline using :-

`transporter run Pipeline.js`

After Initiating this Pipeline, In child Testing Collection we are getting 60 Documents more than Parent Testing Collection.

Initially We don't have any Document in our child Testing Collection and having around 278k records in Parent Testing Collection.

Could you please help if I missed anything to configure.