[{name:"Name1",surname:"Surname1",fullName:"Name1 Surnmame1"},{name:"Name2",surname:"Surname2",fullName:"Name2 Surnmame2"},/** I would like to detect this one where name and name inside fullName do not match*/{name:"Name3",surname:"Surname3",fullName:"Name1 Surnmame3"}]

db.collection.aggregate([{$addFields:{idx:{"$indexOfCP":["$fullName","$name"]}}},{"$match":{idx:-1}}])