This problem could well be because coreutils at some point uses fchmod(4, 0100644) in that test case, and your version of NFS might not take too kindly to that leading "1". Is this something that you can debug interactively? For example, can you do this in a fresh directory:
+ mkdir -p a/b/c a/b/d e + touch a/b/c/foo a/b/d/foo + cp -p --parent a/b/c/foo e except that you run that "cp" under GDB, and put a breakpoint on fchmod_or_lchmod, and see what happens if you manually AND out that leading "1" bit?
