Photoshop CC 2014.1.0 Canvas DPI BUG
If you upgraded Photoshop to CC 2014.1.0 then the Actions from this site, as well as other sites which make cover actions, are now broken.
The error, at least initially, looks to be like an incompatibility with the way the transformation tool works. My initial reaction (as well as my replies to users in the comment threads recently) pointed to this possibility — however, after a few days of fervent testing, it would appear that it’s just a basic mathematical rounding error accidently introduced into the CC 2014.1.0 update. A bug.
Someone at Adobe made an honest mistake.
If you happen to be running CC 2014.1.0 then you need to continue reading — yes, there is a workaround.