gistfile1.py

from mongoengine import *

connect("test")


class Thing(EmbeddedDocument):
    count = IntField()

class User(Document):
    thing = EmbeddedDocumentField(Thing)
    

user = User(thing=Thing(count=1))
user.save()
user.reload() # Getting rid of this makes it work

user.thing.count = 0
user.save()

user.reload()
assert user.thing.count is None