cp -p will preserve times for some files but not all?

On Unix the timestamps cannot be preserved on the files the user does not own.

This is why the following command fails if file1 and file2 are owned by different users in case file2 already exists:

cp -p file1 file2

Seems it is your case because source files are owned by adminrig and target files are owned by tmark.

Not sure if there is a workaround as forcing with -f does not solve the issue.

If you can, try changing ownership of target files...

I know this is old, but I was having the same issue of trying to copy over cifs shares. I have several commands set up in sudoers with the NOPASSWD option and one is cp. If I do sudo cp -r from.file to.file it seems to work. If you have the ability to do sudo, this may be an option.