Thanks for sharing.
My guess is that ICSTOR was describing "missing scenes" from the perspective of testing: scenes are "missing" in the overall flow related to choices made - not because scene content was missing - because they still needed to stitched together all of their content correctly.
It's certainly possible that some content is also missing because they completely missed it, but his sentence otherwise sounds like a side-effect of their Marvel-style (sorta) workflow: create the images first on a plot idea, then flesh out the story text, then code and hope you mash it all together correctly. I think that "mash it all together" step is still in-progress ... hence, "missing scenes" when they test.
Who knows? But, their seemingly big-bang approach of piecing everything together obviously makes this phase more complex for a larger release.