When you compile a query and add it to the Query Store in SQL Server 2016, there can be significant wait times on mutex for accessing the hash map where statements are stored. Therefore, it may take a long time to finish this operation.
This problem is caused by a lock contention issue in the Query Store, where new queries are blocked when they are added to the Query Store. This fix replaces the SEList element with SEListSized, which explicitly holds the number of elements in the list.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.