Bug with caitlyn and sivir, with sivir blocking two spells [GAMEPLAY]

In game, Sivir is going in to spell shield my trap, as caitlyn. I notice, so I use my Peacemaker (Q), so that either she takes the Q, and gets snared by the trap, or she takes the trap and takes the damage. She happens to take the trap with her shield exactly as my Q hits her and she blocks both. So in the end, she took no damage, and the trap was gone. I did not notice if she was given more mana then usual, but she was definitely given some mana back, and effectively spell blocked two spells.