Add limit_choices_to on scope_type

netbox/ipam/migrations/0071_prefix_scope.py

@@ -35,6 +35,7 @@ class Migration(migrations.Migration):
             name='scope_type',
             field=models.ForeignKey(
                 blank=True,
+                limit_choices_to=models.Q(('model__in', ('region', 'sitegroup', 'site', 'location'))),
                 null=True,
                 on_delete=django.db.models.deletion.PROTECT,
                 related_name='+',

netbox/ipam/models/ip.py

@@ -211,6 +211,7 @@ class Prefix(ContactsMixin, GetAvailablePrefixesMixin, PrimaryModel):
     scope_type = models.ForeignKey(
         to='contenttypes.ContentType',
         on_delete=models.PROTECT,
+        limit_choices_to=Q(model__in=PREFIX_SCOPE_TYPES),
         related_name='+',
         blank=True,
         null=True