Keychain swapping my password for Safari Autofill Me instead of the actual password!

I have one website for which Safari and keychain constantly refuse to save the password and instead default to Safari Autofill Me in the password field when logging into it. I reset the password, and it is fine for the first few hours but once I am logged out or return to the site the next day and attempt to login using the password saved in keychain, it has been converted to the words Safari Autofill Me - NOT MY PASSWORD! This only happens on one site, all of my other passwords and logins are fine. please help