It is possible to get in a never ending loop if the lesson is set up to find unseen questions and there is no jump the leads to an end of lesson.
- Create a lesson and in "Flow control" set "Action after correct answer" to "Show an unanswered page".
- The next setting underneath "Number of pages to show" set to "0" for all pages.
- Create just question pages (I recommend multiple choice) with the answer going to the next page and the wrong response directed back to this page. Make sure to add feedback for both correct and incorrect answers.
- Attempt the lesson as a student. Answer all the questions wrong. Observe the never ending loop.
If the student manages to answer just the right answer correctly at the right time, then it is possible to escape.
Adding a content page at the end and setting that page to jump to the end of the lesson will allow students to escape, but answering a question wrong can result in the student immediately hitting the last page and exiting.
Moodle 3.1.2+ (Build: 20161027)
Settings - flow control
Allow student review - NO
Provide option to try a question again - NO
Maximum number of attempts - 1
Each question has:
wrong replies: this page
right reply: next page.
The first question has two answer, one right and one wrong.
The problem has been detected about the first question
If the user give the wrong answer to the first question, he returns to the first question (instead of going to a new question).
If the user gives the wrong answer again, the user returns to the first question again.
If the user gives now the right answer, he goes to a next question and there are not heavy problems, even if the operating of the system is not the wanted one.
But SOMETIME (not for all the users, but only sometime) WHATEVER answer the user gives he gets a page that say: "Maximum number of attempts reached - Moving to next page - Continue"
Sometimes clicking on "continue" everything goes well. Instead, sometimes,
clicking on "continue" the user returns to the first question and now THE USER IS BLOCKED. Whatever answer he selects, he gets the Maximum Number page and the he return to the first answer and so on without end.
Changing the browser (in order to avoid any cache problems) the problems remains.