Clarity using the SQL Server DB throws the following error message during XOG of users, or when attempting to load the 'Items' page of the Add-Ins.
Internal error: An expression services limit has been reached.
Please look for potentially complex expressions in your query, and try to simplify them….
Note: this can happen on any action in Clarity UI, such as Home - Resources - Select a resource in Classic or similar, when a query has a large amount of expressions
Applying CU21 for SQL Server 2019 resolves this issue.