diff --git a/netbox/dcim/forms.py b/netbox/dcim/forms.py
index 6aef5808c..390911f7f 100644
--- a/netbox/dcim/forms.py
+++ b/netbox/dcim/forms.py
@@ -1594,9 +1594,10 @@ class InterfaceConnectionForm(BootstrapMixin, ChainedFieldsMixin, forms.ModelFor
         ]
 
         # Mark connected interfaces as disabled
-        self.fields['interface_b'].choices = [
-            (iface.id, {'label': iface.name, 'disabled': iface.is_connected}) for iface in self.fields['interface_b'].queryset
-        ]
+        if self.data.get('device_b'):
+            self.fields['interface_b'].choices = [
+                (iface.id, {'label': iface.name, 'disabled': iface.is_connected}) for iface in self.fields['interface_b'].queryset
+            ]
 
 
 class InterfaceConnectionCSVForm(forms.ModelForm):
diff --git a/netbox/project-static/js/livesearch.js b/netbox/project-static/js/livesearch.js
index f387372b4..846d2d853 100644
--- a/netbox/project-static/js/livesearch.js
+++ b/netbox/project-static/js/livesearch.js
@@ -43,8 +43,9 @@ $(document).ready(function() {
             real_field.empty();
             real_field.append($("<option></option>").attr('value', ui.item.value).text(ui.item.label));
             real_field.change();
-            // If the field has a parent helper, reset the parent to no selection
+            // Disable parent selection fields
             $('select[filter-for="' + real_field.attr('name') + '"]').val('');
+            $('#select select').attr('disabled', 'disabled');
         },
         minLength: 4,
         delay: 500
diff --git a/netbox/utilities/forms.py b/netbox/utilities/forms.py
index dff06d393..1f37efa08 100644
--- a/netbox/utilities/forms.py
+++ b/netbox/utilities/forms.py
@@ -472,6 +472,9 @@ class ChainedFieldsMixin(forms.BaseForm):
     def __init__(self, *args, **kwargs):
         super(ChainedFieldsMixin, self).__init__(*args, **kwargs)
 
+        # if self.is_bound:
+        #     assert False, self.data
+
         for field_name, field in self.fields.items():
 
             if isinstance(field, ChainedModelChoiceField):