I am also unable to upgrade my Charlatan’s Staff. In my case, I do not ever see the upgraded version – nothing happens when I try to upgrade the staff.
OS: Windows 7
Game version: 1.0.64
Before Bug: Visited the yellow-circle Hermit upgrade shop. With sufficient skulls, I selected the Charlatan’s Staff and pressed the upgrade button.
I expected skulls to be subtracted and the Charlatan’s Staff to be upgraded to Charlatan’s Staff+.
Instead, nothing happens – no skulls subtracted, no upgrade occurs, and I retain the original staff.
All 3 such upgrade shops I have unlocked show the same behavior.
My save file was originally from the demo a year ago, then from an older version of the game a year ago, and only imported to the new version of the game recently.