zombie pigman, when there are multiple, will attack player even when not supposed to

Partner Rank: 3

Verification builds: Beta 1.12.0.4 release 2160393

Summary: zombie pigman, when there are multiple, will attack player even when not supposed to

Impact: Behavior modifications that dont work as they should causes problems with development including halting of projects all together.

Repro Steps:
1. download the attached "monster bug world"
2. summon a single zombie pigman
3. change your gamemode to survival
3. punch it
4. summon a second zombie pigman
5. punch one of them

Observed Results: When there is only one zombie pigman, they dont attack you which is correct as defined by the behavior pack. However when there is a second, they both target you when you punch one.

Expected Results: They should only attack mobs/players defined by their behavior pack

Screenshots/Videos attached:  World is attached.

Regression builds: never worked, at least since 1.2