Defraggler 2.22 unknown/ unsupported buffer szie

I wonder is anyone can help with this, I am running quite a few laptops but where the HDD cache exceeds 16mb defraggler seems to show unknown or unsupprted buffer in the health, is this just a bug or is the drive not working correctly and hence not getting the full speed from the drive? Please see attached picture on clean new Windows 10 home installation. Thanks Nick

defraggler error.png