If you cannot recreate the feature, I don't know what to do. My normal method of trying to fix a Fill Surface that fails after a previous feature is modified is to first make sure that all of the original edges are selected. Second, I unselect and then reselect all of the edges. Third, I try to insert a new Fill Surface ahead of the failed one.
I notice that you have tangent edges selected on a number of faces and contact edges on others. You might want to check to make sure that choice of edge settings hasn't gotten screwed up somehow. You also might want to set them all to contact to see if it will regenerate, then see how many you can get to go back to tangent if it does.
I also notice that you have "Fix up boundary" checked. I only use that when I am really desperate, as it seems to be less robust than picking all of the edges manually.
The solution was to open the part(s) on another machine, make the change, and save as 2014 part. It is kind of odd, but that is the solution so far. The filled surface did not even hiccup on the other machine.
I wanted to add another solution for others like me who come looking: I've had success, rather than taking it to another computer, with simply closing everything and restarting my MACHINE. (Restarting SW itself doesn't seem to be sufficient.)
A reboot solved this exact problem for me.
Thanks for adding your experience with this issue. It has been a while since we had the problem, but I am pretty sure that a reboot did not fix it for us.
This just started happening in one my part models today (SWX 2015, SP5) and the restarting machine trick worked. This is a very bad bug, I'm days away from a 13 part plastics tooling release and I can't have this happening in all my parts. My simple fills can be replaced w/ boundary surfs, but it's all a huge time suck. Is this fixed in SWX 2016?