on the password prompt, the shell automatically adds a return after entering a character and displays authentication failed

Question

logging in to an ubuntu 16.04 server via ssh. This has never happened before. The other user I asked seems unaffected by this. What could have happened? Also, when I try to enter my git credentials and press return, the shell replaces it with ^M, backspace with a ^?. When I open a tmux session, things work as they should.