While playing on multiplayer (only tested on a LAN world) on 1.14.2, if killed while flying with Elytra, you will continue to be stuck in the Elytra after death (crouching or sprinting will cancel it). The player appears upright to other players, however the other players will see their odd physics (sort of like walking on the moon).
1. Fly with Elytra in a multiplayer world
2. Be killed (by any means) while flying
3. That is all
The attached photos and videos show the effects of the bug