Warding Soul, the shielding morph of Wield Soul, currently uses "Area" targeting. While this is suitable for a smart heal, such as the healing morph of that skill, it is not suitable for a shielding skill.
The skill is currently not useful. This is not strictly a bug, but it might as well be, because the targeting mechanic makes it uncontrollable and cripples it for most use cases. Shields are used prophylactically, typically when the target is at full health. However "Area" targeting seems to select the lowest (percentage) health target. Such targets are best healed, not shielded. In the typical scenario where you use a shield, most players are at, or near, full health. This makes the targeting of the shield random. "Area" targeting is OK only for the healing morph of the skill. In fact it's unique and arguably damn strong for that morph, just unsuitable for the shielding morph.
Incidentally, the current targeting of Warding Soul is the same as Healing Ward. However the skills are not comparable, because Healing Ward incorporates a heal and is played reactively, not prophylactically. A better comparison is Annulment. Please adjust the targeting to be either "Self", like Annulment, or "Cone", like Makevolent Offering / Rushed Ceremony.
PC EU: Magblade (PvP main), DK (PvE Tank), Sorc (PvP and PvE), Magden (PvE Healer), Magplar (PvP and PvE DD), Arcanist (PvE DD)
PC NA: Magblade (PvP and PvE every role)