Possibly this is a bug, but I'm not sure. Through user fow in #vim on freenode, I've confirmed no side effect in 7.3.409, but there is a side effect in 7.3.547 (the version on my computer.)
The easiest way to test is to copy paste the following file into a vim buffer, jump to the beginning (gg) and follow the instructions.
Hi there, this is a test case. This line is short. After opening this file issue the following commands: $j:set cuc<Enter>k You'll notice that the cursor should be on the period after "case" this is expected behavior. Next enter the following commands: :set nocuc<Enter>$hj:set cuc<Enter>k You'll notice that the cursor should now be on the word "a" rather than on the "e" at the end of "case" So when you have a column value (not end of line) then :set cuc modifies this value as a sideeffect.
Is there anyway to workaround this issue? Is this a bug? Can anyone else reproduce?