Confused about Prowling Manticore and how it works

Been using Prowling Manticore on my Hell Knight team, I have a Fire Priest who’s attack is boosted by Gonfurian’s relic fused with Apis Majesty. The thing I’m confused about is if this trait is bugged or there’s something I’m missing about the trait.
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What I’m confused about is how the enemy is able to go first before my Fire Priest as it has more Attack. Does speed get taken in account regardless of Prowling Manticore?