Fixed #23894 -- Made deconstruct methods favor kwargs over args

Ticket: https://code.djangoproject.com/ticket/23894
Well, it's not a bug per se, it's more a "zen of Python" thing. And, answering your question, squashing will eventually replace all migrations with that "bug" over time. No need to regenerate migrations, existing will still work.

It also makes Django more behaving itself according to the docs for custom fields: https://docs.djangoproject.com/en/1.7/topics/migrations/#custom-fields