How to reproduce:

Stand somewhere on a flat ground and run these four commands sequentially:

summon wandering_trader ~2 ~ ~ {NoAI:1b,Tags:["e1"],attributes:[{id:"scale",base:0.5}]}
summon villager ~2 ~ ~1 {NoAI:1b,Tags:["e2"],attributes:[{id:"scale",base:0.5}]}
rotate @n[tag=e1] facing entity @s eyes
rotate @n[tag=e2] facing entity @n[tag=e1] eyes 

The expected result would be the wandering trader looking at the player's eyes, and the villager looking at the wandering trader's eyes. But they look much too high. (See attached screenshot).

More context :

I honestly don't know how to describe this issue exactly, as from my testing, the eyes anchor is defined correctly on the new entity's eyes position while being re-scaled. For example running this would show the particle on the entity's eyes location as expected:

execute as @n[tag=e1] at @s anchored eyes positioned ^ ^ ^ run particle soul_fire_flame ~ ~ ~ 0 0 0 0 1 

But re-scaled entities themselves don't manage to retrieve other entities eyes location normally, as they would act as if they were even smaller.