When working on MDL-65634 I assumed that the enrolment timestart is something explicitly set when creating the enrolment. It does not seem to be the case for enrol_self for example. The enrolment timestart is set to time() when the enrolment is createad. The timecreated value was excluded from enrolment_starts_after_calculation_start because it is ok to generate predictions for enrolments that are created after the start time as the course start can be the course timecreated value and enrolments are always added after the course timecreated time. The idea was just to discard enrolments where the timestart was explicitly set after the timestart.

This does not seem to work well and we are seeing it in https://tracker.moodle.org/browse/MDLSITE-5663?focusedCommentId=673872&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-673872. I propose to remove one of the checkings we added in MDL-65634.