[Gameplay] Ultimate available but still shows on cooldown

I've been having some weird stuff happen while playing pyke. As the title says, I see my Ultimate on the last 3-5 seconds of cooldown, but I can also see healthbars in execution range. So naturally, I react and just hit "R" even though there's still a timer, and my Ultimate activates.

I'm also using the Ultimate Hunter rune along with it.