Grim Feast with Cackling Companions (Hysseg's Claw) and/or Wolf Pack

Grim Feast appears to only revive dead wolves from Wolf Pack and dead hyenas from Hysseg's Claw when used immediately after death, with no effect occurring if waiting more than a second or two. Grim Feast still goes through the cast animation even if there's no effect. This occurs when using either companion pack separately as well as when using them together through Yriel's Fostering.

Grim Feast also appears to leave some remnants that cannot be collected. Walking near them with Grim Feast at less than 100% does not work.