I just had the same problem with using "Week 1", "Week 2",...... "Week 10" etc. Week 10 appears in between week 1 and week 2. Week 10 should be the last title in the Module. What I did to correct this was to place a space before the title for week 1 through week 9. This pushed Week 10 to the bottom. It looks fine now in the Student View.
Hope this answers your question.
You should alos be able to arrainge by using the checkbox next to the Learning Module title and the "Move item above" action to the left of the checkboxes.
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