After upgrading from 2.9 to 3.0.1, I have found that my lesson clusters are no longer functioning correctly. The lesson is comprised only of a series of clusters, each with a beginning of cluster that jumps to an unseen questions withing the cluster where a correct answer jumps to the end of the cluster and an incorrect answer jumps to an unseen question within the cluster. The end of cluster page jumps directly to the next beginning of cluster page. For some reason, correct answers are not always exiting the cluster. We found this out from testing another issue we are experiencing since the upgrade where 1 out of every handful of students seems to be presented with a blank question page in the middle of the lesson. The entire page isn't blank, in fact, the only thing missing is the question and answer choices. The header, footer, nav, and even lesson title still appear. For the students getting a blank question, deleting their latest attempt in the lesson seems to be an immediate work around, however a few of those students get the error again in a different place. This issue does not affect every student and we can't find a common denominator with the ones who are experiencing it. We have yet to solve either of these issues, but the clusters not performing correctly is a major issue for us that I need to figure out ASAP as it affects the effectiveness and functionality of the course, which is paid for. Any help would be greatly appreciated! We are on a dedicated server that I have full access to. Please let me know if additional information is needed, I've exhausted every google/moodle search I can for the past few weeks trying to figure this out and paying for a solution is not out of the question for us.

Replication steps.

1. Create a lesson activity with the following settings.
2. Use default feedback: no
   • Allow student review: no
   • Provide option to try a question again: no
   • Maximum number of attempts: 1
3. Add three clusters.
4. Add at least three questions to each cluster.
   • Have the correct answers for each question jump to the next cluster.
   • Incorrect answers should jump to an unseen question in the cluster.
5. Log in as a student.
6. Answer the first two questions of the first cluster wrong, and the last one correctly.
7. Answer the first question in the second cluster incorrectly.
8. Leave the lesson (by navigating away) before attempting any of the third cluster questions.
9. Enter the lesson again.
10. Answer no when asked if you want to start from the last viewed page.
11. Answer the question in the first cluster correctly.
12. When moved on to the next cluster you will be presented with a blank page. As all of the questions have been viewed, the lesson doesn't know what to show the student.