Warwicks "E" bloodscent" speed buff not working, turning it off reactivates [Gameplay]

It seems like this bug occured twice. When I was chasing I had no speed buff on the enemy "below 50 percent health". Looked down the 2nd time i noticed it and saw it was showing activated. It looked shiney meaning "on". when i turned it off it gave speed boost back. I cannot be one-hundred percent certain cause it happened and i just kept playing. I think it maybe occuring though. I dont know the circumstances. 2nd time i was chasing a thresh "It's only fun if they run"