I'm running OSX 10.9.4, and my default shell is set to z shell.
I was just working out my installation of Ruby and RVM and playing around with irb when I suddenly notice that my window title says "bash" instead of my default zsh heading.
echo $SHELL returned
/bin/bash, and I confirmed that I was running bash.
The (temporary) fix was simple - run
chsh -s /bin/zsh, but this instance repeated the switch to bash every time I executed
I was not able to replicate the situation, but I was wondering if anyone had insight into this issue so that I don't run into this error again.