[blocking] Adding ""minecraft:behavior.player_ride_tamed": { }," doesn't override AI goals in enderman

Windows_Minecraft - Release_920093
(Beta 1.5.0.3)

Summary:

Adding ""minecraft:behavior.player_ride_tamed": { }," doesn't override AI goals in Enderman, but it does on other mobs.

Impact: 
I want to make an enderman ridable, this bug prevents them from being usable because they constantly pivot around their AI target including random stroll and targets. Setting a priority doesn't help either.

Repro Steps:

1. See attached demo world with BP
2. tame the enderman with a beetroot
3. ride the enderman around.

Observed Results:
Enderman will often pivot around a certain point preventing smooth walking.

Expected Results:
I expect the enderman to be properly controllable when tamed and riden like a horse. This works on other mobs fine, enderman is an exception

Screenshots/Videos attached:
repro world attached.