Killing Rathound King after truce yields severed head and failed quest

[johnaaron]

"Kill the Rathound King" still fails after negotiating a truce even if you kill him afterwards; Edgar won't accept his head.

This is different behavior than the interaction between Kidnap Sarine/Kill the Rathound King quests as they can both be completed simultaneously.

Thanks,
Aaron

[PaposikG6]

To complete both quests you need to kill him right after Rathoung King rewards you with Regalia before talking to Edgar for the last time.