D&D 5E Where is Trap the Soul???

[Jester David]

i don't think WotC would ever completely tell the truth about why the books came out the way they did. everyone knows that if WotC quit behaving like a giant corporate puppet, they'd fade into the wind like leaves.

It's not some huge mystery or unknowable problem.
They lacked the staff to get all the books out at once, and doing so for 4e caused quality problems. But staggering the release meant people who wanted to could start playing,

 

[Eejit]

The variant Demilich found the spell while wandering the planes and took it from the editing room for itself.