Visual Legend - Repeated indices found in GroupBy or Projections

Dear v-lionel-msft,

I apologize for the late reply. Oddly the enough, the problem seems to have fixed itself. What seems to have triggered the correction was the use of DAX Studio to export the tables one by one. I'm assuming this was a memory key allocation conflict by PowerBI from using multiple append queries, but I can only assume.

Once again, thank you for your help.

Ran into the same error here and fixed it by removing the conditional color before applying the legend. I think the reason for this case is that, some conditional colors have already been applied, and adding a legend column will triggers another usage on multiple colors. Then there's conflict on the color applying rules, and Powerbi just couldn't determine which rule to use for the colors. To solve such confict, you could just give up on either the legend or the conditionale color.