Taxonomy Menu API hooks

I'm wondering if anyone has had any luck using the _taxonomy_menu_insert or _taxonomy_menu_update hooks? When I implement them in a custom module the menu items don't work, ie links are not created when the menu is rebuilt.

The problem seems to be that (line 423, taxonomy_menu.module)

  //let other modules make edits
  $item = module_invoke_all('taxonomy_menu_'. $op, $item);

returns a merged array of $items which the later code cannot understand.

So instead of an array like

$item
  tid => 168

we get an array of the form

$item
  tid
    0 => 168
    1 => 168

I'm thinking that module_invoke_all is the wrong thing to use in this case, and it would work if $item was just passed by reference to each module implementing the hook?

Could write up a patch for this if I'm not completely off track.

Thanks,

Mark