At the beginning, everyone was supposed to tell Hickman where their comics would be 8 months from now. That way, he could write Hickvengers with all of the developments that every other writer did in the next 8 months of comics as if they already happened.
Well, Bendis was in charge of the X-men at the time. Hickman had a bunch of developments like Cyclops starting Nation-X, repurposing the Sentinels to his will, and a number of other things. But Bendis, in his complete ineptitude and laziness, decided to scrap all the original plans and instead take his Original Sin arc and extend it to the point that it for 8 fucking months then ended that arc by timetraveling it such that it never actually happened, then with the ONE issue he had left before the timeline was supposed to match up (which, mind you, was impossible at this point since Bendis took up the entirety of the 8 month lead time to set up these changes on an unnecessarily long arc which was RETCONNED TO HAVE NEVER HAPPENED at the end) decided to go from the originally solicited "AXIS'd Havok and Cyclops decide to start Nation X" and instead devote the issue to Cyclops breaking up with Emma and the Havok portion was relegated to all of one page at the end where they decide to go get donuts. Then Bendis was given one more issue, a triple-sized issue in fact, and it ended up not only not coming out until AFTER Secret Wars, but he devoted like a third of the issue to retconning adult Bobby to be gay.
Basically, Bendis had this laundry list of awesome things he was supposed to do in his X-men run, but he decided "eh, fuck it" and just decompressed one lame arc to fill up the entire gap because he stopped giving a fuck about the X-men by that point.