Django post save signal getting called twice despite uid

I have registered my signal with the callback using the @receiver decorator

@receiver(post_save, sender=User, dispatch_uid='ARandomUniqueString') 
def do_callback(sender, **kwargs):

I have put the from app.signals import * code in __init__.py and I can see that it gets imported twice and I do not think there is a good way to fix it, possibly happening due to installed apps in settings.py. I cannot understand why despite using dispatch_uid and the modelInstance.save being invoked only once, it still runs do_callback twice. Any suggestions?