I recently came across this ticket in when misconfiguring my own Generic Views (I set the queryset attribute instead of the model attribute on an UpdateView)
The ticket in question is #26007 (SingleObjectTemplateResponseMixin.get_template_names does not return names stack properly.) – Django
Relevant code: django/django/views/generic/detail.py at main · django/django · GitHub
I have laid out some options on the ticket which need some input from the community. Let me know what you think what solutions should be pushed forward for this one please!