The data flush task may intermittently take 100-percent of the CPU usage. This may occur when the data flush task moves data from the internal memory-optimized history table of a memory-optimized system-versioned temporal table to its disk-based history table.
Note The data flush task is an automatic background task.
The fix for this issue is included in the following cumulative update 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: