It was not Dibaba but Obiri who dropped a 64 lap to separate herself from the others. So this theory is not correct.
Oh, you're right! Nice catch, and thanks!
The split times on the DL site must've been wrong then, and I got tricked. As you may have seen the screenshots, the split times on the DL site shows Dibaba leading and hitting the 2000m, 3000m, 4000m marks first. That's where I got tricked, but looking at the video again, Dibaba definitely didn't lead for that long and she didn't even get to the 3000m mark before Obiri.
Good catch and thanks, again!