Just some random ideas...
I'm seeing the same issue in Photoshop 13.0.5 running on a 2010 MacBook Pro with OS X 10.8.5. This is the latest version for CS6. One of Noel's reset procedures seems to have cleared up the problem, but not for existing text blocks. New text blocks (created since the various preference resets) now longer manifest the issue.
You can leave smart quotes on — it doesn't trigger the problem for me.
Update: I'm still seeing the same issue on a system running Photoshop 13.0.5 and OS X 10.8.5 on a 2010 MacBook Pro with 8GB RAM installed, 2.7GB free. The intermittent nature of the problem fooled me.
To reiterate the issue as it manifests for me, see also the attached sample screen :
One final workaround that finally has cleared up this issue for me…
The problem appears to be related to the Middle Eastern text display feature, which explains the way that multiple special characters at the end of the line are being displayed right-to-left at the beginning of the line. I am using Photoshop in English and I don't use the Middle Eastern text display features at all, but it somehow seems to be manifesting here.
The workaround is simple:
I found the workaround documented here: