[fixed/closed]Send to Sleep - bad spell mastery

[Aswan jaguar]

Describe the Bug:
Send to Sleep if cast and you have 2 or more instants or & sorceries in your graveyard so spell mastery triggers only the first creature you target gets tapped and gets 2 legacy cards to remain tapped at next controller's untap phase.
If cast without spell mastery works fine.

Which card did behave improperly ?
Send to Sleep

Which update are you using?(date,name)Which type(Duel,Gauntlet,Sealed Deck)
Manalink 2016/01/15: Battle For Zendikar v2,duel

What exactly should be the correct behavior/interaction ?
Send to Sleep

Are any other cards possibly affected by this bug ?
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[Korath]

Fixed 974c2f6.