There is a permanent way to apply Rob's suggestion to get the terminal working:
For the user that is just happy with /sh:
1) Go to Terminal Preferences
2) Scroll down to Shell
3) change /bin/tsch to /bin/sh
Each new window will now launch sh instead of tsch.
For the user that is just happy with /sh:
1) Go to Terminal Preferences
2) Scroll down to Shell
3) change /bin/tsch to /bin/sh
Each new window will now launch sh instead of tsch.