Thanks Sam,
This is really helpful, and we are scheduled to upgrade to the latest minor version in a couple of weeks. I'm not super confident of this fix as you mentioned it happens "for SCORM packages that stored large amounts of attempt data", The SCORM this was affecting is only recording 5 multiple choice questions and it was replicated where they only had attempted the final quiz twice. Saying that I am not sure how much data tries to get recorded with the SCORM packages in general.
Don't suppose there is any other advice we could try in the meantime?