I am encountering the same bug. It first occurred during the quest "At All Costs" after delivering the package to the NPC at the Goose Inn in Copperlane. An infinite XP gain loop initiates after completing this portion of the quest.
In an attempt to resolve the issue myself, I tried to complete another quest to see if the bug would repeat itself elsewhere. Even completing a quest which awarded 0 experience resulted in the same XP loop bug.
This bug is hindering any significant progression on my game file.
Below is a link to the requested files.
https://www.dropbox.com/s/rohyjtq5mt6bh29/PoE-XPbug.zip?dl=0
