I have 3 games uploaded here and and all of them use a password to play, however I am noticing a problem,  having changed the password and logging into run the game it would now appear that the password is invalid. I have typed it in correctly, tried copy and paste method, changed the password-saved and re-tried to login and play only to be met with password invalid, so I am assuming this is a bug

Greetings, I can't understand your question.
You say you have 3 games uploaded to itch, but none appear on your profile.

Itch does not have any password system to play games.

If a game asks you for a password to play, it was the developer of that game who created the password system. It is best to ask that developer directly.