[Answer]-Django CMS losing data from draft to live

You need to implement a copy_relationships method within your plugin model.

When publishing you are literally duplicating the model row. You need to tell the related model how to copy its records and associate them to the correct instance. The CMS allows you to define a method copy_relations which you need to implement.

def copy_relations(self, oldinstance):
    for image in oldinstance.image_set.all():
        image.pk = None
        image.plugin = self
        image.save()

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