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In a recent Modern Masters draft, my opponent cast an AEthersnipe and targeted my Errant Ephemeron with it, returning it to my hand. After he did so I was unable to cast or suspend it. Nothing happens when I click on it or when I drag it over the battlefield. As far as I know, no other relevant cards were involved.

Edit: Bit of an update, it happens with Vedalken Dismisser as well. Also I cast Thirst for Knowledge and chose it as one of the cards to discard. When the spell resolved, the other card I had chosen (Street Wraith) was discarded but the Errant Ephemeron was not. o.o