Steps to reproduce:

> db.test.insert(

{"to" : ISODate("3013-01-01T00:00:00Z"), "a" : 1 }

)
> db.test.findOne()
{
"_id" : ObjectId("5416ba106bb629d51582af74"),
"to" : ISODate("3013-01-01T00:00:00Z"),
"a" : 1
}

$ mongoexport --host localhost -d test -c test --out /tmp/test
$ mongoimport --host localhost --db test -c test2 -file /tmp/test

> db.test2.findOne()
{
"_id" : ObjectId("5416ba106bb629d51582af74"),
"to" : ISODate("3013-01-01T00:00:00Z")
}

In general, every field which appears after "to" field will not be imported. When I use lower years such as 2039 it works.