When I hold down "w" to walk (I have the default key bindings), if I hold it down for too long I auto-walk. "Too long" is a matter of seconds, not even minutes. This happens every game session, sometimes within minutes of starting. I can reproduce it just by holding "w" down.
Usually, pressing "w" again will cancel it, but sometimes it doesn't. I generally next try opening the pip boy or swapping weapons, and sometimes it works but sometimes those keys are non-responsive. I then try to F9 and restore from my last quicksave. Sometimes that works, sometimes I come back into the game still walking, and sometimes that key fails to do anything and I need to escape out to the main menu. If that is non-responsive I need to cntrl-alt-del out, and sometimes even that is non-responsive and I need to physically push the button to reboot. In no case does clicking the actual auto-walk key help.
I recently upgraded; this happened on Windows 7 and 10, two different USB keyboards, two different motherboards, different video cards, the works. That means that I've also checked the obvious - the keyboard is new, clean, and not sticky; I've tried three different USB ports; I don't have a joystick or other device installed; and I did re-install the game.
I remember this happening in New Vegas, too, and google searching suggests that this is not an uncommon issues, but I've not yet seen a fix.
Thoughts?