Target Heal/Buff does not work as required

1. Title: Target Heal/Buff does not work as required
2. Reproduction Rate: 90 %
3. Blocker? My wife is swearing a lot and is considering stopping to play healer. I would say that is a blocker.
4. Details: The "center target" is always gaining priority over the "Tab/g/F2-F8" target. This results in "Selfbuffs/heals" of the healer instead of the intended target, due to an enemy (?) moving between her and the target (me). Having an enemy between me and her is nominal behaviour for our duo to get the "attack from the back" bonus.
   This is also the case if I am slightly off angle. Also my or her elementar are often gaining heal or buffs instead.
5. Steps to Reproduce: Dont try this at home. She can get quite mad. (She is using mouse mode thus her character view is not linked to her screen view)
6. User Specs: N/A.