Fixes #4880: Fix remove untagged-vlans if not assigned in bulk interfaces edit

docs/release-notes/version-2.8.md

@@ -6,6 +6,7 @@
 
 * [#4875](https://github.com/netbox-community/netbox/issues/4875) - Fix documentation for image attachments
 * [#4876](https://github.com/netbox-community/netbox/issues/4876) - Fix labels for sites in staging or decommissioning status
+* [#4880](https://github.com/netbox-community/netbox/issues/4880) - Fix remove tagged vlans if not assigned in bulk interface editting
 
 ---
 

netbox/utilities/views.py

@@ -721,8 +721,8 @@ class BulkEditView(GetReturnURLMixin, View):
 
                                 # ManyToManyFields
                                 elif isinstance(model_field, ManyToManyField):
-                                    getattr(obj, name).set(form.cleaned_data[name])
-
+                                    if form.cleaned_data[name].count() > 0:
+                                        getattr(obj, name).set(form.cleaned_data[name])
                                 # Normal fields
                                 elif form.cleaned_data[name] not in (None, ''):
                                     setattr(obj, name, form.cleaned_data[name])