Nunu (and sivir?) bug.

I was playing and leashing for on red buff. When Call of the Freljord procs to me, it gives me a buff that says Undefined. It did not give me the additional attack speed. Here are the steps to reproduce what I had.

1. Have a Nunu and Willump (our's forgot smite but I don't think it matters)
2. Play Sivir? (Again, I don't know if this matters)
3. Proc Nunu's passive on Sivir
4. Mouse over buff to see Undefined as the spell
5. Fix the bug!