This command:

var builder = Update.PushEachWrapped("ArrayData", new List<GenericListItem>
{
new GenericListItem()

{ Name = "name", Surname = "surname" }
});


It is translated in :

{ "$push" : { "ArrayData" : { "$each" : [[{ "Name" : "name", "Surname" : "surname" }]] } } }

that is wrong, due to a [ in sub elements.

The right command translation has to be

{ "$push" : { "ArrayData" : { "$each" : [{ "Name" : "name", "Surname" : "surname" }] } } }

otherwise a sub array will be created.


The same problem is also present in :
PushAllWrapped
AddToSetEachWrapped
PushEachWrapped

There is a possible workaround forcing the conversion between IEnumerable<T> to Array. So re-writing the above code in this way

var builder = Update.PushEachWrapped("ArrayData", new List<GenericListItem>
{
new GenericListItem()
{ Name = "name", Surname = "surname" }

}.ToArray());

create a correct serialization.

It seems that the problem is located here in UpdateBuilder.cs

BsonDocumentWrapper.CreateMultiple(values).Cast<BsonValue>();
(public UpdateBuilder PushEachWrapped<T> ... raw 1309 in UpdateBuilder.cs) wrap each values in an array