Storyline 360 interactions not displaying in published LearnDash Course??

Hi, I've created a LearnDash course, which has a lot of Storyline 360 content (lessons uploaded as zipped packages using 'xAPI (Tin Can API) in 'Reporting and Tracking' when publishing in SL). We have all the necessary Uncanny Owl extensions/plugins.

During development and testing, the SL interactions were visible to everyone involved with the course. Now we have published the LD course, to be viewed by learners, all the Tin Canny content has simply disappeared (although I and others can still see it when we are logged in as an admin). The course is intended to be 'open to all'.

Has anyone come across this before? 

Many thanks!

Cathy