Playing my Rogue deck just now. I run two Shadowstep but otherwise singles in this deck. I had one of my Shadowstep cards and Zephrys in my hand, so no duplicates in my deck. Zephrys wasn't highlighted yellow. I tried playing it anyway (thinking the lack of highlighting was the bug), and the lamp animation triggered but not the wish mechanic. Very frustrating. Anyone else having this problem? Naturally HSTracker failed to upload the replay.....
Whenever my Reno/Kazakus/Zephrys doesn't turn gold in my hand, it's because a card or cards have been added to my deck, and I now have unexpected duplicates. That is what happened to you, even if you can't remember the circumstances. Either that, or you made a mistake with your deckbuilding.
The lamp animation is related to Zephrys's summoning, not his battlecry.
The greatest likelihood is that it is one of the following: - You accidentally put an extra copy of something else in your deck - Your opponent shuffled something into your deck (like a bomb etc) - You used something like a Spell Lackey which gave you a Shadowstep and you mistakenly thought that it was the one from your deck - You used a card like Lab Recruiter and put a copy of something into your deck
That doesn't mean it isn't possible for it to have been a bug of course - but the likelihood is fairly low that it was. :-D