I'll go full tin hat mode here. Set up the sequence. If Maggie prepped Thomas, when she ran, to act as the conduit for her death curse, then it's arguable that she knew Raith could get at her and in fact she planned for it. He might have had the ritual completed as soon as he was sure she had escaped. Knowing he would do this she went to someone who could hide her. In Turn Coat Summer hides Morgan from the Senior Council, no mean feat. So posit Lea as her benefactor. With herself shielded, the curse just waited. What was the payment? Harry as a Starborn. A possible weapon against the Outsiders. The protection lasted until she produced the payment. And at his birth the curse came home to roost. Malcolm was collateral damage. Taking Lea's tough love philosophy to their natural limits, she murdered Malcolm or caused him to be murdered and name dropped Harry to Justin, in a bid to temper her weapon. Considering the smile on his face maybe Lea had Lara do Malcolm, that's pretty twisted.