[elwell]

Perhaps our consciousness existed in some spiritual way, but no memories got translated to our biology.

[swayvil]

You ever walk into a room and forget why you walked in?

I think changes in perspective break memory.

Greater changes mean greater breakage.

Walking into another room is a change. sleeping, dying, Weird drugs. Those are also changes.

Also, there is a degree of breakability/flexibility, inherent to the person. Depending on various stuff.

And there are ways to become more flexible too. Less prone to breaking. This leads to phenomena like "lucid dreaming".