I had this same issue before 1.0.0
16w50a too, and fireworks stop working with Elytra when this bug occurs
The bug eventually came back after a little while. It is like I am flying, whenever I get hurt I jump like 5 blocks and the glide, same thing happened when I jumped.
This is the same problem I am having with the newest snapshot, 17w48a.
It happened twice, right after one another.
This is the important part of the game log: