Django forms.ModelMultipleChoiceField not saving anything - django

Question

I have had so many problems with forms.ModelMultipleChoiceField and widget = forms.SelectMultiple I'm hoping someone can put me out of my misery.
I'm using the JQuery Chosen multiple select box (similar to Select2) to render out the interest field in the ProfileUpdateForm on the font-end.
At first the request.POST was not executing at all, the submit button wasn't clickable and I got the error An invalid form control with name='interest' is not focusable which I have now patched by adding
def __init__(self, *args, **kwargs):
super(ProfileUpdateForm, self,).__init__(*args, **kwargs)
self.fields['interest'].required = False
to my ProfileUpdateForm.
Although I can now click the submit button and see
[2019/02/18 08:26:53] HTTP POST /profile 302
and all other form information updates ...nothing happens to the forms.ModelMultipleChoiceField interest field.
If you select an interest then press submit, the SelectMultiple field is empty on page refresh and nothing is stored / saved. I've checked the admin and nothing has updated in that section.
What is the best way to proceed to diagnose the problem?
forms.py
class ProfileUpdateForm(forms.ModelForm):
interest = forms.ModelMultipleChoiceField(
queryset=Interest.objects.all(),
widget = forms.SelectMultiple(attrs={
'name': "interest",
'data-placeholder': "Choose your interests",
'class': 'chosen-select',
'multiple tabindex': '4',
}))
def __init__(self, *args, **kwargs):
super(ProfileUpdateForm, self,).__init__(*args, **kwargs)
self.fields['interest'].required = False
class Meta:
model = Profile
fields = ['interest', 'age', 'bio']
views.py
def profile_view(request):
if request.method == 'POST':
p_form = ProfileUpdateForm(request.POST,
request.FILES,
instance=request.user.profile)
if p_form.is_valid():
p_form.save()
messages.success(request, f'Your account has been updated!')
return redirect('profile')
else:
p_form = ProfileUpdateForm(instance=request.user.profile)
context = {
'p_form': p_form,
}
return render(request, 'users/profile.html', context)
profile.html
<form method="POST" enctype="multipart/form-data">
{% csrf_token %}
<!-- edit Profile model info -->
{{ p_form|crispy }}
<button type="submit" value="submit">Update Profile</button>
</form>
<script>
$(".chosen-select").chosen();
$('button').click(function() {
$(".chosen-select").val('').trigger("chosen:updated");
});
</script>
models.py
class Interest(models.Model):
interest_name = models.CharField(max_length=30)
class Meta:
ordering = ['interest_name']
def __str__(self):
return self.interest_name
class Profile(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
interest = models.ManyToManyField(Interest)
bio = models.CharField(max_length=200)