1. Get hit by a Shulker, receiving the Levitation effect.
2. Press jump to activate your Elytra.
3. Deactivating the Elytra by landing or pressing jump again will deactivate gliding and Levitation will continue as normal.

I expected to keep floating upward because of Levitation.

Instead, I was able to glide as normal, as if not under any effects at all.

By controlling when I was levitating and when I was gliding, this bug gave me quite a bit of vertical control when fighting Shulkers in End Cities. This made what I normally find to be a frustrating encounter to be more interesting and dynamic.

Video Demonstration: https://youtu.be/r5slIqi6wwo