If this is accurate, then it just takes me back to my original thought: the Russos should have done a better job conveying that old Cap had arrived from an alternate timeline.
I think this is a fair criticism. Arguably, the easiest way to do this would be to have old Steve appear on the pad at the moment he was supposed to return and then tell his story. The issue I see with this is that earlier in the film, something like this happens to Scott but it's a sign that something went wrong so I feel like if they'd gone this way many in the audience would be confused and/or would think it was a joke.
What they did was, I think, more artful but, yeah, it does give the impression that he lived with Peggy in the Prime Timeline and that's been confusing people too.
Bruce says that Steve missed his exit while traveling back. That could just mean that Steve actually came back a lot earlier, while The machine was unattended, or even before The big battle. Or, The Russos just simply liked it better having him just appear there, without too much thought of exactly how he came back.
This sounds good. If we believe that people can only travel back to the Prime Timeline using the pad, he could have arrived, like, the night before, when nobody was looking, then gone and hid behind a tree.
(For some reason, I'm very attached to the idea of Steve hiding behind things and popping out at just the right moment.)
I posted this before but to me, it's less about not creating an alternate timeline so much as not dooming an alternate timeline to a world without their Infinity Stone.
Yes, I'd wholeheartedly agree with this.
This whole conversation between Banner and The Ancient One is throwing people a lot. When they talk about erasing a timeline I think what they mean is that they're erasing "the problem with a timeline not having all six Stones". None of the timelines can just be erased nor can they be reconciled with the Prime Timeline where events played out quite differently.