This might depend on the published settings of the SCORM package and therefore what the package is returning. 

For example, in Articulate Storyline: 

- There are settings in the Publish menu for Reporting and Tracking, which indicate what is reported back to Totara (ie Passes/Incomplete or Complete/Incomplete). This needs to match the completion requirements in Totara.

- Additionally, it is possible to include a trigger that creates the course completion record.

Hope this helps.

Cheers, Simon