Killed jungler with red buff, got both red and blue buffs

Nami vs Jax - Bug with the buffs
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As you can see in the video after killing Jax who only had red buff, while I didn't have any, I got both red and blue buffs. Wasn't I supposed to get only the red off him?? Did this happen for any reason I don't know or is it actually a bug? Or maybe Jax had both but blue wasn't showing? I only noticed later when watching the replay. Asking before I send a bug report through the client.
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