Collectible Card Game Headquarters

This is part of a log where computer is playing ponder (a very difficult thing to force AI to play with pre-arranged test decks, it really does not like to play the ponder):

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Computer activated Mutavault3
00:00:45
Computer cast Ponder to reveal top 3 cards from Library
Computer put 3 cards on top of Computer's Library
00:00:43
Computer resolved effect of Ponder
Part or all of the ability/spell's resolution has failed [CTriggeredSearchLibraryAbility::ResolveSelection() - AbilityTriggered1.cpp(132)]
Computer resolved effect of Ponder
Computer drew a card
Computer resolved effect of Ponder
00:00:42
Computer cast Winged Sliver3
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Apart from the weird message, after the third resolution message I got priority and passed (this is computer's turn and log is concise unfortunately) and AI got priority again and cast Winged Sliver.