I already know another way to get around this issue. So, I don’t want to know the solution. I would like to know the reason. I try to parent eye to the very top bone. I press CTRL+P and choose Bone. The eye jumps to another location. I don’t know why. I’ll attach the blend file so you can try yourself. Is it a bug in blender? Parenting Eyes issue…blend (719.5 KB)
I didn’t download the file, however it should depend on the position of the objects when you are parenting, but you can solve it by selecting the ‘Keep Transform’ option.
Or, the eyes could have some constraints.