^L showing up in Emacs M-x shell-mode, with ksh but not bash

[Nicholas Papadonis]

When Emacs is invoked in an X-session and when I resize a M-x shell-mode
*shell* window by more then a single line of text, $PS2 is being output in
the shell mode window.  When I type <return> then a number of "^L"s are
also output in the shell mode window.

I'm using /bin/ksh93 in Debian.

This behavior does not occur with bash.

Does anyone know why this is happening?  Also, more ways to debug it?

Thank you