How can I fix this unexpected Windows Event Log message which appears whenever a database with FILESTREAM is created or restored?
It could be two things. If you have Windows 10, Creators update, there is a patch for the SQL Server.

In all other cases this fixed the error for me:

ALTER DATABASE [dbname] SET ANSI_NULL_DEFAULT ON WITH NO_WAIT
GO
ALTER DATABASE [dbname] SET ANSI_NULLS ON WITH NO_WAIT
GO
ALTER DATABASE [dbname] SET ANSI_PADDING ON WITH NO_WAIT
GO
ALTER DATABASE [dbname] SET ANSI_WARNINGS ON WITH NO_WAIT
GO
ALTER DATABASE [dbname] SET ARITHABORT ON WITH NO_WAIT
GO
ALTER DATABASE [dbname] SET AUTO_CLOSE OFF WITH NO_WAIT
GO
ALTER DATABASE [dbname] SET CONCAT_NULL_YIELDS_NULL ON WITH NO_WAIT
GO
ALTER DATABASE [dbname] SET QUOTED_IDENTIFIER ON WITH NO_WAIT
GO
ALTER DATABASE [dbname] SET PAGE_VERIFY NONE  WITH NO_WAIT
GO