Grand Total shows null when applying filter on calculated field (CASE statement)

Looker Q&A Looker
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1

Hi Community,

I’m facing an issue in Looker Studio where the Grand Total shows null when a filter is applied on a calculated field, but works fine when all values are selected.

Details:
Table with dimension - AB Tasty Campaign and Metrics: Total Users, Form Submits, CVR, Bounce Rate, Avg Engagement Time

Filter control on Campaign Type which is Calculated field:
Code:
CASE
WHEN CONTAINS_TEXT(AB Tasty Campaign, “PZN”) THEN “PZN”
WHEN CONTAINS_TEXT(AB Tasty Campaign, “LIVE: AB Test”) THEN “AB Test”
WHEN CONTAINS_TEXT(AB Tasty Campaign, “A/A”) THEN “A/A Test”
ELSE “Not Defined”
END

Issue: Selecting one Campaign Type shows Grand Total null and Selecting all values shows Grand Total shows correctly
Is this a limitation with calculated fields or filter behavior in Looker Studio?