Auto-casting for subdocument._id not work

[Crotery]

I have a schema
{
...
windows: [{name:String}]
...
}
If I run Model.find({windows._id:'string'}) everything is ok, mongoose is sending query {"windows._id":ObjectId('string')} and returns records;

If I extend the schema somehow (ex. just {S_V:Number}),
find() do not return anything, because mongoose is sending query {'windows._id':'string'}, which searches for string-type _ids and fails to find any.

This issue contains more information and real code example: Automattic/mongoose#3364 (comment)

[sieira]

May have to fix the cloning stuff, I'll check that