Angered Pigmen Do Not Run Fast Enough
This seems to be a partial regression of MCPE-12443, but I've created a new ticket as I think the base issue is different.
Angered pigmen do not run fast enough; the player is able to outpace them by walking.
According to the wiki:
When aggravated, their speed will significantly increase to faster than the player's walking speed.
I think changing the speed multiplier from 1 to 1.5 in the vanilla behaviour file for this mob would fix this:
"minecraft:behavior.melee_attack": { "priority": 3, "speed_multiplier": 1.5, "track_target": false },