Latest Report Server version with Custom Security Extension

Hi All,

I tried to downlaod and install latest version (Version 1.1.6582.41691 (Build 14.0.600.442), Released: January 10, 2018) of PBIRS and tried to configure it with Custom Authentication as per forlloing: https://github.com/Microsoft/Reporting-Services/tree/master/CustomSecuritySample. Everythings works fine and I can successfully login using custom authentication.

However with Admin user when I tried to upload new dashboard (pbix), I get following message:

There was an error uploading your .pbix file. Verify that the file has not been corrupted and that the file extension matches the format of the file.

Please note, 

• I am already using same PowerBI desktop optimized for this Report Server. (downloaded along with Report Server). And this pbix uploaded successfully before adding Custom Security Extension.
• I even tried to change "Service Account" in configuration manager to use with Local Administrator user but same
• I also tried to use database "sa" account but no affect.

With old version of Report Server (Version 1.1.6514.9163 (Build 14.0.600.434), Released: November 1, 2017) I was able to Upload and review Dashboard after implementing Custom Security.  So it seems this new version of Report Server does not support Custom Security Extension. Please need official confirmation and any possible workaround  v-yulgu-msft v-qiuyu-msft

Thank you in advance.