Notice: Undefined index: tid in apachesolr_multilingual_term_reference_indexing_callback_implementation

Getting the following notice everytime I try to index into Solr:

Notice: Undefined index: tid in apachesolr_multilingual_term_reference_indexing_callback_implementation() (line 309 of sites/all/modules/apachesolr_multilingual/apachesolr_multilingual.index.inc).