How old is the SSD and was it heavily written to? Did it have large files occupying a majority of its capacity which were written once and then never changed?
Having a large area that's written once and not changed matters for flash drives but it doesn't matter for SSDs. As the life wears down on other cells they'll take that stationary data and move it.
Furthermore, a SSD that end-of-life locks should become read only, not simply vanish.