Dataset with value NULL is showing the last KPI value rather than NULL

When a KPI is pointing to a dataset whose vlaue changes to NULL, the value in the KPI stays as the last non-NULL value reported. I'd like it to update to NULL... or blank or zero by default.

I do not want to create another measure that changes a NULL value to zero. 

I think this is just a bug that needs to be fixed.

I am on PowerBI Report Server Version 1.1.6551.5155 (October 2017)... we do plan to upgrade to the latest version (March 2018) soon. If someone knows whether the latest version fixes this, I'd definitely appreciate the info! :)

Kevin