Distinctcountover error - Your calculated field expression contains invalid syntax

I tried creating distinctcountover calculation of userid, with two partitions fields - (1) 'breakdown_field 'and (2) ‘Test/Control Groups’.

I succeed creating the calculated field, but when I tried inserting it into the visualization - I got the next error: " Your calculated field expression contains invalid syntax. Correct the syntax and try again.
In the ‘Show Details’ section, the source error is: “sourceErrorCode:DISTINCTCOUNTOVER_INVALID_ARGUMENT”

(1) ‘breakdown_field’ - contains a parameter which define the breakdown column to present:
(2) ‘Test/Control Groups’- contains 2 parameters which define if the user defined as ‘Control’ or ‘Test’

Can you please help me with this issue?

In you visual do you have both the Test/Control Groups and Breakdown_field? To use a window function you need to also display the fields that it is partitioning by.

Another thing I noticed is that you could be referencing Test/Control Groups twice in your distinctCountOver field if you select ‘Test/Control’ with the BreakdownBalances.

This might not be an issue but have you tried taking that case statement out?