My fingers remember my iphone passcode. but my brain doesn't.

I have had the same iphone passcode for over a year now. Yesterday, I tried logging in so many times that my phone locked 3 times and I ended up not logging in once that night.

I was so weirded out by the fact that I completely forgot the passcode which I had been using all year. My problem gets even weirder the next day.

This morning I logged in out of habit, entering the passcode out of muscle memory without thinking. After realizing I had just done with such ease what troubled me for hours the night before, I logged out again to see if I could figure out my password.

This time I was thinking about what I was doing, and since I don't actually know the passcode I couldn't get into my phone. This has been bothering me all day.

You see, every time I remember that I forgot the passcode, I can't think of it. But If I log in without thinking about what I'm doing, theres no problem. My fingers simply type on autopilot.

I realize now that I should probably change the passcode. However I can't log in with that intention in my mind, because then I remember that I don't know the passcode.

Am I the only one in the world who has ever had this problem? It is the weirdest thing and I worry my brain is malfunctioning.