Originally Posted by Jennifer
I was wondering this too, and it would certainly make sense that Doc would be duplicated too. All we know about the DeLorean in 2025 is that Doc found out that Griff found it and Doc stopped him right before he damaged the timestream.
The 1885 DeLorean was damaged, so the 2025 DeLorean would have to be fixed. It's possible Griff took the DeLorean from Doc in 2025 when he was fixing it, and the other Doc saw only Griff with the DeLorean and just assumed just the DeLorean was duplicated, leaving Doc stranded in 2025.
I was also wondering, with the fact that Doc was a whole different person from Double Visions on, what the new timeline would be like. At the very least, it would seem that some events would be different since Doc was completely secure with his inventing to the point where he was openly living in 1986 in that timeline, so that Doc doesn't seem like the kind that would destroy the time machine. Since the events happened differently, I wonder whether the temporal duplication occurred at all in the new timeline since all the variables would have to line up very precisely for that event to happen.
It's a slightly different doc but he would have had to go through MOST of the time jumps the old doc did; Jules and Verne still exist so he'd have gone through the same path up to and including getting stuck in 1885. Now one key time jump which changed is that this doc eventually returned to 1985 to live (and has stayed there the last six months) whereas the old doc has been gone for six months.
It certainly is possible for another doc to have been stranded in 2025. Though how would our doc know about the duplication? He did indicate they were considering sending Verne to college in the 2020's so he and Clara have likely been there.