I've sent the output_log and savedata to the email.
Steps to Reproduce the fps drop Issue:
When you start a fight and kill all the enemies,the fps drops a little.And then,quickload,but the fps does not return to normal.
You may not notice the fps drops at first,but after a long period of repeatly fight and quickload(half an hour or more),you'll see the significant fps drops(especially when you move around).
I reproduce the issue in The King's Coffin(Dunnage).Other places also have the problem.It seems to have nothing to do with the locations.