[Game Play] Yorick and Muramana

Has anyone else come across a muramana activation bug? I'm not sure what the catalyst is but at a certain point in game I was not able to activate Muramana and recieve the buff anymore. I could press the activation hotkey and the Muramana would animate as if activated, however my auto attacks were not buffed or making the extra sound on hit. It may have been after ulting myself and dying at some point.