Well, I just watched TFA again (enjoyed it just as much as every other time) and I think I have a pretty good guess as to why Han looks so "off" in that shot. I think it is a pickup shot filmed post-accident but before he was fully "back on his feet" so to speak.
In addition to his hair being different, looking more tired, etc. it always struck me that he seemed to be holding himself funny, more like a "frail old man". Then today I noted that he doesn't move below the waist much at all, and certainly doesn't take any steps. It's like he's rooted in one spot. (Once they try to imply movement, but he's really just shifting his weight and pivoting a little at the hips to imply as is he's about to take a step, but that's it.) I think his leg is in a cast or he is on one of those "knee wheelchairs" or something else propping him up but also keeping him stationary. Watch the scene again and it becomes pretty noticeable.
That's the only scene in the film where his injury is even slightly noticeable (to me). Perhaps it was just a pickup shot because they had to get the shot at an exterior location before moving on, so maybe they asked him to do before fully healed, which would also explain why his appearance doesn't match any of the shots before or after.
M
