Afraid CS50 Lab and CS50 Sandbox are currently missing some configuration files, the result of which might be that terminal windows' prompts (i.e., shells) might look a bit different than expected. And commands like `make` and `python` might not behave as expected. We've rolled out a temporary fix, and a permanent fix should be rolled out soon. In the meantime, you can run
curl -s https://gist.githubusercontent.com/dmalan/65a92cd701b1dd8ee4d8f07414e4bb07/raw/f98809205e694d3ef9fae101cb989ab1d5c95fb7/cs50.sh
in a terminal window to fix existing labs and sandboxes manually. Note that you'll then need to open (via the + icon) and use a new terminal window to see the new settings, rather than continue using any already-open terminal windows.
Sorry for the trouble!