Machine translations that are inserted or autopopulated in the CAT Tool are stored in the Translation Memory and are counted as Processed Words because the action of submitting the translations is executed by a human.
Machine Translations (MT) that are processed through an initial MT workflow step are not saved to the Translation Memory (TM). Saves to the TM could happen if there are additional human steps after the initial MT step, or if there are any edits made to the MT.
If Machine Translation proceeds to an Edit or Review step type, this will lead to Machine Translation saving to the Translation Memory. This is because any content submitted or saved in an Edit or Review step type is considered "human" translated content. So, even if Machine Translated content was unchanged in any of those step types, it will be saved to the Translation Memory.
If you want Machine Translations to be processed through an edit step after the initial MT step, ensure your workflow includes a Post-Machine Revision step type as the "edit" step. This will avoid having any unedited Machine Translated content save to your TM. However, any edits to an MT on this step will result in saves to the TM.
If a Machine Translation was edited and saved by a user in the CAT Tool (outside a Machine Translation Post-Edit step type), in the TMM itself, or in the Strings View, the edited Machine Translation will save to the Translation Memory.
If you want all Machine Translations (edited and unedited) to be saved to the Translation Memory, consult your Customer Success Manager.