Sporadic KeyError for 'email' in UserCreationForm

[nicolazilio]

Hello,

I am experiencing an error for which I can't find an origin, hopefully you may have some insights. Every now and then Django complains that email is not in self.fields[User.USERNAME_FIELD], see below

I can see that it isn't in self.fields but why it isn't is not clear to me. If I restart my app, it works no problem for a while, until when the problem appears again, and the only way to solve it is to restart the app.

My UserCreationForm looks like this

class UserCreationForm(UserCreationForm):
    """
    A UserCreationForm with optional password inputs.
    """

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields["password1"].required = False
        self.fields["password2"].required = False
        # If one field gets autocompleted but not the other, our 'neither
        # password or both password' validation will be triggered.
        self.fields["password1"].widget.attrs["autocomplete"] = "off"
        self.fields["password2"].widget.attrs["autocomplete"] = "off"

    def clean_password2(self):
        password1 = self.cleaned_data.get("password1")
        password2 = super().clean_password2()
        if bool(password1) ^ bool(password2):
            raise forms.ValidationError("Fill out both fields")
        return password2

and add_fieldsets is set as follows

add_fieldsets = (
        (
            None,
            {
                "description": (
                    "Enter the new user's name and email address and click Save."
                    " The user will be emailed a link allowing him/her to login to"
                    " the site and set his/her password."
                ),
                "fields": (
                    "first_name",
                    "last_name",
                    "email",
                    "is_pi",
                ),
            },
        ),
        (
            "Password",
            {
                "description": "Optionally, you may set the user's password here.",
                "fields": ("password1", "password2"),
                "classes": ("collapse", "collapse-closed"),
            },
        ),
    )

Any ideas?

Thank you very much in advance.