diff --git a/app/controllers/ops_controller/settings/common.rb b/app/controllers/ops_controller/settings/common.rb
index fcd1dfb5c29c..1d7980f43df2 100644
--- a/app/controllers/ops_controller/settings/common.rb
+++ b/app/controllers/ops_controller/settings/common.rb
@@ -806,6 +806,8 @@ def settings_get_form_vars
       field = "ntp_server_#{field_num}"
       next unless params.key?(field)
       @edit[:new][:ntp][field] = params[field]
+      # remove unnecessary key from @edit[:new][:ntp] if there is no change
+      @edit[:new][:ntp].except!(*field) if params[field] == @edit[:new][:ntp][:server][field_num - 1]
     end
   end