Assume that you connect to a SQL Server 2017 Analysis Services (SSAS 2017) tabular model from Power BI desktop. After upgrading to Cumulative Update 13 for SSAS 2017, when you run a Data Analysis Expressions (DAX) query that contains TREATAS function, the query may fail with an error message that resembles the following:
"An unexpected exception occurred."
This issue is fixed in the following cumulative update for SQL Server:
About cumulative updates for SQL Server:
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server: