Why does softaculous keep losing my Prestashop install?

Twice now, when I've gone to uninstall Prestashop, softaculous/cpanel/whatever-it's-called didn't recognize it was installed. The first time, my installation had become corrupted, and I was going to uninstall and re-install it. (I assumed I had corrupted it with a bad code change.) This time, there is still a working shop at salvagehunter.com/presta/index.php, but when I go to uninstall it I can't, as softaculous doesn't admit it exists. What is going on???