Originally Posted by PhailRaptor
This is true, however, if Teemo is the target of the attack, he should not also be hit by the splash riding on the Blinded attack.
Apparently this was confusing, so I'll elaborate, starting with a question:
Was it an auto-attack directly from Trynd to Teemo that killed Teemo, while Trynd was Blinded?
If Trynd was attacking Teemo directly, then Teemo should not be an eligible target for Tiamat's splash damage. If this was how Teemo died then it's a bug and needs to be fixed.
If Trynd was attacking Teemo, realized he was Blinded, and switched to a nearby minion, then Teemo should have been killed as normal by the splash damage from Tiamat, coming off of the minion to hit Teemo.
If Trynd was swinging away at Teemo while Blinded, then realized he could use the Active effect on Tiamat for the kill, then it is working as intended.
If Trynd used Ignite, the entire question is null and void, because Tiamat splash isn't what killed Teemo -- Ignite is.