Fixes #8919: Fix filtering of VLAN groups by site under prefix edit form

docs/release-notes/version-3.1.md

@@ -14,6 +14,7 @@
 * [#8813](https://github.com/netbox-community/netbox/issues/8813) - Retain global search bar query after submitting
 * [#8820](https://github.com/netbox-community/netbox/issues/8820) - Fix navbar background color in dark mode
 * [#8850](https://github.com/netbox-community/netbox/issues/8850) - Show airflow field on device REST API serializer when config context data is included
+* [#8919](https://github.com/netbox-community/netbox/issues/8919) - Fix filtering of VLAN groups by site under prefix edit form
 * [#8932](https://github.com/netbox-community/netbox/issues/8932) - Fix error when setting null value for interface `rf_role` via REST API
 * [#8935](https://github.com/netbox-community/netbox/issues/8935) - Correct ordering of next/previous racks to use naturalized names
 

netbox/ipam/forms/models.py

@@ -222,7 +222,7 @@ class PrefixForm(TenancyForm, CustomFieldModelForm):
         label='VLAN group',
         null_option='None',
         query_params={
-            'site_id': '$site'
+            'site': '$site'
         },
         initial_params={
             'vlans': '$vlan'