Create a timed test, which does not permit submission beyond the due date.
1. Start the test near the due date (in particular, at a time when the time limit would normally expire after the due date).
2. Stop the test
3. Start the test in a browser that goes to a different front end processor
4. Your time limit will be too small. The error is equal to the difference in time between when you started the first time and the second time.
In DeliveryBean, it set timelimit to the minimum of the time limit for the test, or if you're near the due date, the due date - current time. That sounds reasonable until you consider what happens if this is a restart, i.e. if the user started the test, when out and came back in. I believe you want to set the time limit to the due date - the begin time, not the current time, given that in the end you're going to apply the time limit to the whole time since start, not just the time from now.
This problem is reproducible.