cvs update -d updates entire repository?

[weberjacob]

I have a strange problem. I'm in the root directory of my workspace. I
type:
   cvs update -dP module/dir1/dir2/dir3/
because I want to update only the files in dir3. Instead, it starts
checking out every single module in the repository. But if I leave off
dir3, it updates dir2 as expected. What is going on? I'm using cvs
1.11.19.
Jacob