Access token setting expiration times

I have seen many posts about how to prevent token expiration but I am currently looking for the opposite solution,

It seems the expiration in my tokens is being ignored. The following is the embed token code snippet in my ASP.net dashboard controller, posting the token to an Angular 2 front end to be fetched and displayed in an iFrame using the powerbi-client.js library.  

var embedToken = PowerBIToken.CreateReportEmbedToken(bi_workspaceCollection, bi_workspaceId, bi_Id, expiration: DateTime.Now.AddMinutes(5.0)
, UserID.ToString(), roles: new List<string>() { "UserAccess", "UserDataSourceAccess" });

Is there something I am missing in my approach? Any help is appreciated.

Thank you for your time.