Months later I still believe episodes 8 & 18 and 17 & 18 were cut so they could be played in sync. Some interviews have appeared over the past week that add to the mystery:

"David did a couple of scenes here and there that only he knew what was going on. On those scenes, I roughed something out, but I didn’t even have a clue what was going on.... So a scene like the atomic bomb, the so-called episode eight. There were certain scenes like that that only he knew what it was supposed to be, sort of making up the effects as we were going along." 

Duwayne Dunham

"In terms of editing, for example, Duwayne Dunham and the other editors assembled the material in the order that they saw it, and then David went through it and looked at everything, and he would change things or edit things on his own after those guys left. David continued editing for six months after the whole editing team left."

Sabrina Sutherland