I had the same problem once. It turned out the rvm-script got loaded twice, which broke things a bit.
Check all the files that load when you open a shell:
/etc/profile
~/.bashrc
~/.bash_profile
and so on, and make sure they don’t load RVM twice.
Maybe put
echo "Going to load RVM"
before
[[ -s "/Users/user/.rvm/scripts/rvm" ]] && source "/Users/user/.rvm/scripts/rvm"
in your ~/.bash_profile to see if it happens or not.