Assume that you use In-Memory OLTP together with Always On availability groups in Microsoft SQL Server 2016 or 2017. If the availability group is configured to use the synchronous-commit availability mode, you may notice a temporary decrease in performance for In-Memory OLTP transactions.
To check whether you are experiencing this issue, check the SQL Server 2016 XTP Transactions:Transactions created/sec performance counter. You might be experiencing this issue if there are any regular drops with an interval of about 30 to 60 seconds. Additionally, the Database:Log Pool Total Active Log Size and Log Pool Total Shared Pool Size performance counters could have the same change pattern (for example, the size decreases to zero with the same interval).
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.