I have the exact same symptoms like the OP. Those seem to be introduced in recent versions, cause it worked before. I am currently on 1.5.15.
I can reproduce the issue like follows:
CMD+I on a file on a drive nested in one or more folders. It shows the place of that file as:
/Volumes/Drive/folder/file
when I unmount and remount the drive and do the same again, I see:
/folder/file
When TotalFinder is in that situation, I cannot rename or open that file. Also when dragging that file into Terminal.app the path is wrong.
When I restart Finder and TotalFinder everything works normally again.
Marc