I have an old world (generated before 1.7.2) and since the snapshots for 1.13 and up until now when i use a firework to activate an elytra i have infinite impluse duration, it never decreases and i can fly infinitly. Most of the time that prevents chunck loading. Even if i remove the elytra during this i continue to fly.

I tested this with newer worlds (generate them in the snapshots/pre-releases for 1.13 and in more recent full versions and load them in the latest update) and this doesn't happen.