Windows jump to different monitor when I type a number
I use a USB to VGA adapter and my adapter came with a program called "super utility" and aside from providing shortcuts to monitor settings, it provides the functionality of assigning hotkeys to move windows between monitors. Mine acted exactly as you describe, acting almost as if sticky keys were enabled (which mine are not) I was not pressing the combo for doing such a function, however, when I disabled the utility, it fixed the issue.
I hope this gives you something else to look into.