Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.1
This is really a question about ssh, not about coreutils, so I suggest
bringing this up in an ssh format. That being said, try debugging your
problem with 'sh -xc' instead of plain 'sh -c'. You'll find that the
problem is not with 'cp'.