: Notes date from June 2001. When was Eternal released?
2008, 2004, or 2000, depending on what level of "release" you want. (2000 was "it's never going to be done, and Bungie is dead, so here's the design docs and work in progress" release; 2004 was the "it's playable, I'm sorry it still sucks" release; and 2008 was the "good enough" release. Expect a "I'm finally happy with it" release by the time the world ends in 2012).
It's possible I saw that bit in the Arrival notes and tweaked the story to incorporate it somewhere in there, but most of the story (aside from the several complete overhauls to Chapter 5, which have nothing to do with the S'pht) was pretty set in stone by the time the project "died" in 2000.
I'm just noting that something I thought I had made up was actually canon (or protocanon) all along. I've been saying things like "my theory is that..." or "in my interpretation..." when I could have just left those qualifiers off.