Mid 2012 non-retina MBP 15", 16gb RAM, 1tb SSD. MacOS 10.13.2. 10.13.3 never showed up in app store updates. So I downloaded the .dmg file from Apple. When I clicked install a popup said it could not on my machine. It's pointing me to a document about installing on fusion drives. But I have an SSD, and am already on APFS. I decided to just skip this update and not force the issue. But I'm curious as to why this is happening.