Flame wall damage

Hello guys.

I have a problem in POE2 which i cant solve.

Me and my friend play at party. He plays witch and one of his spells is flame wall with support gems (Arcane Tempo, Fortress, Mobility). When I cast Spark after he summons that flame wall damage to enemy minoins damage my energy shield. I cannot solve that problem. Can you help me?

Thanks a lot.

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