here's a little vid I made a little bit ago about the common cause of ghost shifting. Many people spend time adjusting high/low limit screws, changing cables, and otherwise waste time and money replacing parts that aren't the cause. Not that these other items can't cause the issue, just most commonly it's the hanger... Note that most often you DON'T need to replace the hanger!! this one was actually cracked, but most often you can slightly tweak it back into place. They are designed to bend easily to help save your derailleur from impact damage!!
I Did this quick, soo... yaaa there are a few mis-spellings here and there.. but you'll get the idea ;)