Rod of Ages not developing or showing stacks [GAMEPLAY]

I purchased a , and several minutes later, it still had not begun to build stacks. Instead of the normal "(300 + 0) Health", it showed "(300 + Unknown) Health, and the same for the Mana and Ability Power stats. In this situation, I was playing as on the Howling Abyss. This is the only time I've ever seen this happen, so unfortunately I can't confirm what conditions were present or not in order for it to appear. [IMG]http://i65.tinypic.com/2rraq1z.png[/IMG].

Game was at 8:37, and I had also purchased a at the same time. Not sure what other information is relevant.