When viewing the ideal line in a burndown chart, there is a large discrepancy between how much time the ideal line is starting with and how much time is assigned to tasks.
The ideal line is computed when hours are entered into a task's Estimate and To Do fields. Under normal circumstances the To Do and Estimate fields would match when the task is created, however if the Estimate and To Do fields do not match, then there can be a discrepancy in the ideal line when viewing the burndown chart.
This would be considered a training issue and users should not enter more hours into the Estimate field than are contained in the To Do field.