Bizarre directory delete behaviour on SSD drive

Directory c:\test has 50 or so files in it, no subdirectories.

    If IO.Directory.Exists("C:\test") Then
        IO.Directory.Delete("C:\test", True)
    End If

    IO.Directory.CreateDirectory("C:\test")

Drive C is Intel's X25-M80 SSD drive, OS is Windows 7 64 bit with TRIM support, Visual Studio is 2008 with target framework 3.5. When above code is executed, CreateDirectory breaks code execution without an (visible) exception. After much headache I found that Delete is not yet done by the time code execution gets to CreateDirectory. If I modify my code like this:

    If IO.Directory.Exists("C:\test") Then
        IO.Directory.Delete("C:\test", True)
    End If
    Threading.Thread.Sleep(2000)
    IO.Directory.CreateDirectory("C:\test")

then everything works as expected.

My questions beside the obvious WTF here are:

• shouldn't IO.Directory.Delete be a blocking function call no matter what the drive is
• is SSD "cheating" on delete due to enabled TRIM support?