Same save as comment 456, under SVN 3491 (from about an hour ago), the huge inflation value is gone, but there's still a huge overcharge somewhere. When I loaded the save, it indicated I had a surplus of 71 gold per turn, which went hugely negative (-350ish with 0% research) after recalculating, so maybe there's some issue with the recalculation (still)?
What do you mean by Overcharge ?
in your save, the next turn (2269), IA 13 choose Tech : same issue as Joseph and Questdog game - it take more than 4 min to evaluate all building/Units that can be build with each Tech (~70 different ways). after that turn 2270 is better, but for turn 2271, the same IA choose again another Tech.
on my Computer (SVN 3489):
Turn 2269 : 12 min 52
Turn 2270 : 5 min 56
Turn 2271 : 8 min 56
About Gold per turn, the inflation goes from -268 to 0, and the civics cost rise from 35 to 82. That's why you go from +71 to - 267 gold per turn (with 100% research).