Why do those accidentally dead mutants resurrected have all their memories？

[PotniaTheron]

I remember Professor X only updates mutants' mind store once a week.

[Gray Lensman]

I remember Professor X only updates mutants' mind store once a week.

It hasn't become important to the story yet. At some point a writer will want some relevant knowledge to be discovered but not by certain characters, at which point we will see a gap appear - and someone will likely know they have a gap but not what it was supposed to hold. Learning what it is will likely be the MacGuffin that drives a story arc.

[PetPigeon]

In X-Force Domino literally says she doesn't remember what happened to her specifically just knows she went through some trauma and she chose for it to be that way.

[JB]

We might see more of this in X-Factor as well since it's dedicated to resurrections.

[H-E-D]

Not sure who you're talking about specifically.