Bounty Hunter capped at 5% [gameplay]

Bounty hunter has a bug where it only amplifies damage by 5% at 5 kills, rather than 7.5% like it should. I went into a custom game and killed 5 enemy bots once each. I then hit some minons and took note of the damage.

At max bounty hunter stacks, I did 117 damage to the minons when I had 112 AD. This meant my dmg was amplified by 105%, which aligns with my hypothesis that BH caps at 5% dmg rather than 7.5% implied by the tooltip.