I found a reproducible bug in visor mode.
If I have a dual panel visor open and try to change the file extension of a folder on the right side of the visor, the Finder hangs and can only be restarted by force quitting it and restarting TotalFinder afterwards.
I know it is unusual to rename a folder to have a file extension, but this is a bug nonetheless.
In my case, I was creating a VPN configuration file by putting the according preferences text files into a folder and then renaming the folder to .tblk, which is the proper file extension for the VPN program, as advised by the software company. This works flawlessly in the vanilla Finder.
This is on Mac OS X 10.7.5.