Comment 89 for bug 39315

On the IBM Bios Update site i've found the changelog regarding this issue:

Version 1YET62WW (1.27)
Note: This BIOS version will only work with Embedded Controller Program
Version 1.06 (or higher).
      * Previously released BIOS version 1YET60WW, 1YET61WW and Embedded
        Controller 1.05 combination may cause a spontaneous wrong key
        input when you key input with an external PS/2 type keyboard.
              * Numeric characters (2, 4, 6 and 8) will be inserted
                internittently during cursor move with cursor keys.
              * A keyboard behaves as if shift key depressed until a
                shift key is pressed.
                      * You can only type only Uppercase characters.
                        (Some keys seem to keystrokes, because the shift
                        cases are not defined)
                      * Multiple selection with cursor keys
                      * Numeric keypad will turn to cursor keys

        If you encounter these cases, please update the Embedded
        Controller to 1.06 (1YHT29WW).

So I suggest to all a BIOS-update, where it's possible.

It seems that the problem is solved by me now...