MongoDB slow query over an empty collection that has a watch - mongodb

Question

I'm relatively new in MongoDB.
I have a single MongoDB instance in replica set in order to use 'watch'. We are currently watching on 'insert' events over the 'removeCollection' collection, the point is this collection is always empty (so noone is inserting anything there right now).
But the log is suddenly showing the below "slow query" message dozens of times. When this happens, the cpu consumption increases a 20%.
{
"t":{
"$date":"2022-11-16T09:15:45.836+00:00"
},
"s":"I",
"c":"COMMAND",
"id":51803,
"ctx":"conn522936",
"msg":"Slow query",
"attr":{
"type":"command",
"ns":"ventusproxy1.removeCollection",
"command":{
"getMore":2257121337268066828,
"collection":"removeCollection",
"batchSize":2147483647,
"$db":"ventusproxy1",
"$clusterTime":{
"clusterTime":{
"$timestamp":{
"t":1668590144,
"i":14391
}
},
"signature":{
"hash":{
"$binary":{
"base64":"AAAAAAAAAAAAAAAAAAAAAAAAAAA=",
"subType":"0"
}
},
"keyId":0
}
},
"lsid":{
"id":{
"$uuid":"47ffbf37-2a66-4b6f-bfb0-57f0e83075e2"
}
},
"$readPreference":{
"mode":"primaryPreferred"
}
},
"originatingCommand":{
"aggregate":"removeCollection",
"pipeline":[
{
"$changeStream":{
}
},
{
"$match":{
"operationType":"insert"
}
}
],
"cursor":{
"batchSize":2147483647
},
"$db":"ventusproxy1",
"$clusterTime":{
"clusterTime":{
"$timestamp":{
"t":1668590004,
"i":1046
}
},
"signature":{
"hash":{
"$binary":{
"base64":"AAAAAAAAAAAAAAAAAAAAAAAAAAA=",
"subType":"0"
}
},
"keyId":0
}
},
"lsid":{
"id":{
"$uuid":"47ffbf37-2a66-4b6f-bfb0-57f0e83075e2"
}
},
"$readPreference":{
"mode":"primaryPreferred"
}
},
"planSummary":"COLLSCAN",
"cursorid":2257121337268066828,
"keysExamined":0,
"docsExamined":17228,
"numYields":13243,
"nreturned":0,
"queryHash":"8D9BAD8C",
"reslen":319,
"locks":{
"FeatureCompatibilityVersion":{
"acquireCount":{
"r":13244
}
},
"Global":{
"acquireCount":{
"r":13244
}
},
"Mutex":{
"acquireCount":{
"r":1
}
}
},
"readConcern":{
"level":"majority"
},
"writeConcern":{
"w":"majority",
"wtimeout":0,
"provenance":"implicitDefault"
},
"storage":{
"data":{
"bytesRead":89
}
},
"remote":"10.1.0.7:36266",
"protocol":"op_msg",
"durationMillis":210
}
}
I have searched trying to find a reason for that ... no luck. And I honestly don't know where to start. I would really appreciated if someone could point me to the right direction.
Thanks,
Joan.