[GAMEPLAY] Zilean's passive not giving back the xp he gives out if the target travels too far

It's all in the title, really. Zilean's passive gives him back the same amount of experience he gives out. However, if your target (that you are giving experience to) travels too far away, they still get xp and level but, Zilean does not get that experience back. I just had it happen to me three times in one game where a Riven would travel too far using her skills (twice) and someone else recalled during the xp transfer.

I suspect it has to do with the way Zilean gets the xp back. After Zilean gives xp and levels a teammate, there is a little projectile that flies back at Zilean which is the "xp return". Zilean gets the xp when the projectile reaches him. When a teammate moves too far away that projectile is never spawned and thus Zilean does not get the xp.