make sure we only wipe values once

I'm using drupal to do community accounting and I intend to have the transactions categorised and indexed. I am very happy you are working on this module.
Because of the financial nature of my entities, my entity controller sometimes inserts and updates in the same page request. With your module, the terms aren't cleared for the second operation, resulting in a db_insert error in taxonomy_entity_index_field_attach_update

Could I suggest the module wipe the terms on an update and not on an insert, rather than only on the first call per page load.