Why does deleting Parent effect create offset?

[nuxttux]

Hi,
When using the Parent effect or the Track effect on Object, I noticed that deleting the Track / Parent Effect results in the the Object being moved to a different location - an offset is created.
This also happens when disabling or hiding the Track / parent effect.

However this does not happen if I set the target to None before deleting the parent effect.

Is there a way to avoid that offset (without setting to none first)? Thus keeping the Object in the same location it was before deleting the Track / Parent effect.

On that same note, is there a way to change the origin location of an object? So that the Alt+G doesn't move it to the upper left corner?

I did notice that putting objects in a group seems set the origin location to where the object was when the group was created.