This issue may be observed when you upgrade to SQL Server 2017 or during SQL Server 2017 server startup.
If the number of In-Memory OLTP databases in the Availability Groups exceeds the number of CPU cores in the computer that hosts a secondary replica, the databases that have In-Memory OLTP may not complete recovery.
This fix is included in Cumulative Update 4 for SQL Server 2017.
About SQL Server 2017 builds
Each new build for SQL Server 2017 contains all the hotfixes and security fixes that were in the previous build. We recommend that you install the latest build for SQL Server 2017.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminology Microsoft uses to describe software updates.