No, I don't think its Syanna Vernon combo causes this problem, after i played like 10 cards the game stucked just like pic2 i couldn't end the turn. I've seen Flake had the same problem when he played double Vran and bunch of spiders the game froze.
The first is Cintrian Knight can't damage your own unit which the description doesn't specify.
The next 2 pics show when i played double Syanna and double Vernon (played 10 cards in one turn), couldn't end turn and the games breaks.