ELM 9.2 Mandatory Learning function

When using Mandatory learning after a mass enrollment, we had learners who previously completed the class or were dropped from the roster be re-enrolled into the class,. We have had the learning period set for the period of time the class needed to be completed. We set historical credit to the day the mass enrollment was performed. No renewal was needed so it was left blank. Here is my question;

If the system looks at enrollment status and sees the learner has completed it why would it re-enroll if the renewal is not activated and why would it re-enroll dropped learners? Should it not look at the enroll status and if there is one and the criteria set forth is met...not re-enroll any of these learners? Some insight would be helpful on this process.