I'm pretty sure when nighthound or fayde are attacked when invis, they get revealed for and fade back. There was one time I was playing rhapsody and I got my stun on fadye but she turned on her ulti to run away. I thought I lose the stun counter but apparently it still worked so I spammed it before it went off and didn't see her?! Geomancer also had his ring of death on her so we could sorta see where she went but it was odd.. don't stuns or damage reveal invis?