My student has read a book completely. "Words Read" count is showing the correct data but "Time Spent Reading" is showing "Zero" mins.

The time spent reading is based on when the user opens the page and when they click on next button to turn the page. The difference of time when the page is opened and turned to next page is considered as time spent on the page. As per the design, if the user navigates between the pages within a minute it captures the time spent as 0 minutes.