Using the REST API, trying to move database records to another database category will always fail even for valid catagory IDs (numerical).

Looking at the relevant code segment in \applications\cms\api\records.php it seems that moving categories erroneously assumes a blog is being edited.

Can anyone confirm and/or suggest a workaround

 

You should be able to send a REST API POST request to the record and pass 'category' in as the new category.

I don't understand what you mean by "it seems that moving categories erroneously assumes a blog is being edited". If that was a typo and you meant 'record' instead of blog, then that is accurate - moving the record will effectively be an 'edit'.