Course causing Moodle to log an attempt despite exam attempt not being made

I have a new module which i'm testing on our Moodle LMS.

All settings in the course (as far as I can see) are consistent with our other modules, and the LMS settings are definitely the same as per our other modules. I've swapped out and tested multiple other modules' SCORM packages within this new module set up and they all behave as expected, which leads me to believe there is an issue with the storyline course somewhere rather than the Moodle settings/LMS.

Learners should be able to leave and resume the module at any time (they are prompted by the player settings). They get two attempts at the final exam. After the second attempt Moodle forces a new start, so learners start at the beginning of the module, and can re-work through the module if they like and have a second attempt.

The issue i'm experiencing is that learners are only prompted to resume the module ONCE. If they leave and re-launch the module a second time, a new attempt is forced and they start back at the beginning. A '0' score is logged against their first attempt in Moodle and a second attempt is started. Similarly, they can only exit and re-launch the course once. After that, the module opens in review mode.

I'm led to believe it is something to do with the exam that is causing this as when I removed it and republished I continued to exit and enter the module and never entered a second attempt, the resume worked at every stage.

Please let me know if you have any thoughts! I'm using Storyline 360 .