The Bug

The creeper fuse animation does not take its Fuse NBT value into account.

To reproduce

1. Execute the command

   /summon minecraft:creeper ~ ~ ~ {Fuse:2000}

2. Use a flint and steel on the summoned creeper.
3. Notice that the animation stops well before the creeper explodes.
4. Execute the command

   /summon minecraft:creeper ~ ~ ~ {Fuse:20}

5. Use a flint and steel on the summoned creeper.
6. Notice that the animation is not played completely before the creeper explodes.

Original description

If a creeper's fuse length is shortened, it will explode before the animation is complete. If the fuse length is lengthened, the animation stops after 30 ticks, so the creeper will simply not change until it explodes.

This is the same bug as MC-2490, just for creepers instead of TNT. It's a little harder to fix, since the creeper animation includes expansion in addition to the flashing. The best fix would be to simply change the speed of the creeper expansion to match the fuse length. Alternatively, the creeper could just keep expanding until it explodes, but that would lead to very oversized creepers for long fuse lengths.