Wait for condition in the change workflow uses the condition as start_date<=javascript:gs.minutesAgoEnd(0)^EQ. When the current date is greater than start_date, the workflow remains at the wait for condition and does not move forward.

The wait for condition on the workflow began before the condition was satisfied and there is no update on the record to allow the condition to be evaluated. This is the expected behavior for the Wait for Condition as per the documentation: https://docs.servicenow.com/bundle/newyork-servicenow-platform/page/administer/workflow-activities/reference/r_WaitForCondition.html.

An update to the parent record or a nudge on the workflow context will resolve the issue. To automate this better, use a workflow timer activity that is relative to the start_date. The workflow timer eliminates the need for an external event.