If translation source node is deleted, cache is not updated correctly

It would not be normal in a production site, but if a translation "source" node is deleted without previously deleting all its translations, then the MultiLink cache will not be properly updated, because translation_node_get_translations() will no longer return relevant translations. The result is that links may be shown to the deleted source node, resulting in a 404 if they are clicked. Since ML does not provide a way to manually clear or rebuild its cache, there is no simple solution. User would either have to edit all relevant ML links in content, or clear the ML cache via db tools.