Ctrl key being always pressed even with the spring removed

Hi, I have a problem an old Model M: left ctrl key appears to be constantly pressed. I thought to remove the spring and put it back in, or get a replacement if its damaged, but the issue persists even after I removed the spring (I also removed the other ctrl just to be sure). It sometimes gets unstuck after hitting some other buttons, seemingly randomly, but the problem returns after a restart. Does anyone know how what could be done to fix it?