Undo Button bug

I was in an ARAM as veigar, and noticed I still had my poro snax when I was dead. The icon was lit up like I could use it since a poro was on my body. I laughed at the thought of feeding a poro while dead and bought my Athenes. I then tried to use the poro snax and nothing happened, and I couldn't undo my athenes for a void staff.