Steps to replicate

1. Create a new Scrum Board using a new Project that has no issues yet
   
2. Create a new issue but do not fill the Original Estimate field
   
3. Create a new Sprint and start the *Sprint
   
4. Ensure that the Estimation Statistic is set to Original Time Estimate and use the Remaining Estimate and Time Spent for Time Tracking
   
5. Switch to the Chart Mode of the Rapid Board and the Guideline is displayed as a hortizonal line dividing the Y-Axis and the value 0 is placed in the middle of the Y-Axis
   
6. Switch to the Plan Mode and edit the issue to include an *Original Estimate of 20w
   
7. Swicth back to the Chart Mode and it can be seen that the 0 value is in between the Y-Axis and the X-Axis and somehow, the Guideline does not appear on the chart. This is due to the fact that it overlaps the X-Axis, causing it not to be visible