Forget about it. Its your controller. I have 2 Dell M6300 laptops with sandisk Ultra 256Gb and they both show the same symptoms, however both have been chugging away for over 2 years ime. When i moved one Ultra to another laptop for a few weeks the errors stopped piling up and the health never dropped below 88% Wouldn't sweat it tbh. Seems theres some weird Sandisk attribute in SMART that causes this, i've not experienced data corruption (SFC'ed them now and then) or problems, just the annoying SMART reports.