Could you let me know if the steps I'm taking are not what you meant. I'm not seeing a bug with the steps I'm taking to repro the issue. It is possible the saved score was out of sync with the pose that was saved…
1) I deleted all of my autosaves for 682.
2) I loaded up the puzzle and tried Restore Very Best to make sure there wasn't anything there, it restores to the initial configuration
3) I loaded in your solution which scores as 11841
4) I Restore Very Best and it stays as 11841
5) I wiggle for a short time and the score changes to 11881 because of the core existence bonus
6) I Restore Very Best and it stays at 11881
I've tried various other actions after loading in your quicksave to see if it changes anything. I've wiggled sidechains, turned the 'disable slow filters' on/off to force Foldit to rescore everything. It doesn't change the core existence bonus. I've checked in the code and it's definitely running through that filter.
For the 11841 score, it is considering these residues as core:
4, 8, 11, 15, 18, 22, 25, 29, 32, 36, 45, 52, 56, 59, 63, 66, 70, 73, 77, 86, 90, 93, 97, 100, 104, 107, 111, 114, 118
For the 11881 score, it is considering the same as core plus 39. The wiggle changes the backbone enough so that one residue goes from not being considered to being considered in the core.
If I'm missing the issue, then could you clarify what you meant by the bug? Thanks