That is interesting, Henk
I know that earlier releases of Windows 10 were having problems with SSDs on a Raid assembly, which was sorted on later editions, but have not heard of anything as specific as your post.
I think this is serious enough to discuss in the Microsoft forums, and, for all, to provide feedback. The Defrag is on by default. For the unwary, this could potentially lower the life of the SSD.
Could you give me any links or info on the subject of ols SSDs, as I would like to take it further.