Gamerules such as doFireTick are only applied to the overworld. As a result, fire spreads in the nether and the end.

This has been a long-standing problem with SpigotMC, but not with Vanilla.

Possible solutions:

1. Have per-server gamerules, instead of per-world.
2. Send gamerule commands to all worlds.
3. Split command registration to per-server and per-world. Would probably require a default interface method somewhere.