500 Internal Server Error

Error: native function error - in rm_get_field:
   Index+ error: request for invalid sub-field (2320) mus_part_obj_num.1.mus_part_obj_num_display
***  in native function "rm_get_field"
***  call: rm_get_field ([ix_recmon_record], "mus_part_obj_num.1.mus_part_obj_num_display")
***  call: X_MI_get_metadata_structured_data ("O4377", "object", "OG")
***  call: MI_add_metadata_meta_tags ([TABLE], "O4377", "object", "OG")