Iceblood tower/arcane brilliance bug

I only had one spell in the deck (Mask of C’Thun) so my Iceblood Tower was going to cast it at the end of the turn (2nd proc), then I casted Arcane Brilliance to get another copy, but it gave me nothing. It’s like the tower stole the spell before casting it.

Most likely you reduced the cost of your Mask of Cthun with a card such as Incanter’s Flow. In that case the Mask won’t get copied by briliance, because it costs 6 now.

Good point, that’s a possibility.