Steps to reproduce

1. Open Fireworkies.mcworld . This world contains a repeat command block that tracks a firework's alive-time on a scoreboard, a command block for resetting the score, and a command block for running the test. The test command block teleports the player 500 blocks away, into a contraption that teleports the player back as soon as possible while another repeat command block spams the chat. The number of "away" statements in chat represents the number of ticks during which the player was 500 blocks away from the firework rocket.
2. Step on the pressure plate to the left to reset the score.
3. Crouch and use a firework on the pressure plate to the right.

Expected result

The firework rocket does not get ticked while its chunk is not simulated, therefore, the lifetime shown on the scoreboard after it explodes is between 22 and 31.

Observed result

The lifetime shown on the scoreboard after it explodes is often much less than 22. This means that the firework's life-timer was incrementing on ticks in which the command block in the same chunk was not being ticked.