Translation:My father's first wife is my half-sister's mother.
I don't know if reporting the problem explains why i flagged it. But I wrote this "my fathers first wife is the mother of my half sister" and the notifications says there is a mistake because I put a space between "father" and "s". Which I clearly did not. If it wants to call me out for anything, at the very least call me out for the missing apostrophe!
The new Dutch tree is very buggy still. They're trying to fix small errors like that.