Gantt Chart - Hide Extra Dimension?

[cbaqir]

I have this cool view via a Gantt chart to look at a single ticket's journey. It includes class buckets to indicate the number of days in each step. It looks like this when selecting DEFECT_ID 2466:

The problem, however, is visible if you click on a Queue step like ERC - Routing. As you can see highlighted in yellow, one of my dimensions  DEFECT_GPQ_START is showing instead of the 7 day buckets. How do I get this field to not display on my chart but remain as a dimension to maintain the functionality? I still want to see the  <7, >21 etc class buckets on the y-axis.

thanks!