I’ve created a fiddle to reproduce the issue: https://jsfiddle.net/9r12m3e7/1/
In the console you will see it returns a data array of 24 which contains duplicates.
This issue seems to happen when Subtotals and Grand Totals are turned off and Columns only contains the “Values” default column. I’ve set up the slice in a specific way to reproduce the issue 100% of the time.
Thank you for pointing this out to us.
Our team will provide the fix for this in the minor release with the ETA 15th of July.
As a temporary workaround, we kindly advise to turn on Subtotals and Grand Totals before using
Please let us know if this works for you.