On my cloudshell instance, I did a 'sudo yum install kbd', which allowed me to use a command line tool called 'showkey'. This command line tool echos the key presses that it detects.
Running it via 'showkey -a', so that I could use ctrl-d to exit from it, when I press the 'ctrl-k' key combination, to my bafflement, it echos that I just pressed the ctrl-L key instead!
As a comparison, running 'showkey' on my local Ubuntu machine, it correctly showed that I pressed the 'ctrl-K' key.
Why does this matter? Because I use ctrl-K to edit command lines. It typically maps to the Gnu readline's 'kill-line' (functioning as a kill to end of line).
BTW, I've noticed this same bug/issue appearing on my Cloud9 environment as well, when I open up a terminal from within Cloud9.