Halvar God of Battle bug
I had the Halvar God of Battle on the board.
I had an Angel with an enchantment on it so at the beginning of each turn you can attach target aura to that creature. My opponent put Faith's Fetters on my creature blocking all abilities that were not mana related.
The problem: At the beginning of each turn it asked me to click on the target to apply the double strike effect from Halvar. Because of Faith's Fetters it would not let me do that which is fine except I couldn't not do it either. I could not click on anything at the each turn and had to wait until I burned all available timeouts and then forfeit my turn. This happened each turn, there was no way to do anything but wait and lose my turn. Finally after ten rounds or so my opponent destroyed the angel that had Faith's Fetters on it and we resumed as normal.