One of the advantages of taking online courses is that a user can do it at its own pace.

In the trainings a user is now seeing a warning in case he did not stay in the item page for the time it was 'designed': "Hey! Please take some time to go through the content in the page, if not, we can't say you've completed it!". And if he is not in the page for more than that time, the item will not be marked as completed.

The time a page is open doesn't reflect if the user read it. This metric to mark something as complete should be removed. 

There are users that need less time to read than others, and in some cases there is irrelevant information or information already known. But the training should not force a user to have the window open just for the time to pass. The mandatory time might make people to go to other pages till it passes, losing focus.

Like as other companies do in their online training, time should not be the factor to mark as completed. 
A quiz at the end of each topic/chapter can help with the metrics, repeatable till a user passes it.