Firework rocket use while flying slows player down

A player wearing an elytra and flying level is propelled by a firework rocket to a speed of 33.459m/s. When flying downwards at a higher speed and then using a firework rocket, the player's flight speed is lowered to ~34m/s.

Expected behavior: Using a firework rocket while flying at higher speed than firework rocket propulsion should not slow the player down.