ParticleSystem parented to object parented to Humanoid hand is jagging when ROTATING only.

Hello everyone, I have a problem with a Particle System that is parented to an object that is parented to a humanoid's hand. When moving the character at any speed in any direction, the visual origin of the ParticleSystem always stays dead on center.

But when rotating the character, the ParticleSystem "lags" be$$anonymous$$nd, like its position is updated at a slower timestep.

I have no scripts that affect the ParticleSystem, I had an IK script for the character but I turned that off to see if it was the cause.
I disabled IK Pass on every layer in the characters Animator Controller for the same reason. The jagging stays.

I created 3 empty GameObjects.
Nr1 is rotating constantly by a script.
Nr2 is parented to Nr1 with x = 0.5 so it moves a distance constantly.
Nr3 is parented to Nr1 with x = 1.
I created a new ParticleSystem and parented it to Nr1 with x = 1 and then to Nr3 centered.
No lagging.

The simulation space is Local, so it should never derive from the parent position at all. Does anyone know what is causing t$$anonymous$$s?

Edit: Particle Systems seem to be totally bugged when parented to a bone-animated object. I tried deparenting and reparenting at multiple $$anonymous$$erarchy levels of the object and suddenly the ParticleSystem stays at a local y-offset to the character, no matter what height the hand bone (parent) is moved to, the system renders at a height offset of about 0.5 units from the root bone.

I also strongly believe t$$anonymous$$s "bug" is noticable since Unity 5. I remember not having t$$anonymous$$s kind of problem with Unity 4.6 where the new UI was introduced.