External Keyboard not working in BitLocker screen (E6330)

I installed several E6330 with Win10 Enterprise and BitLocker encryption.

When the laptop is docked in the keyboard stops working at the BitLocker password screen. Before that (BIOS) and after that (Win) the keyboard works. 

To top it all the error is inconsistent in it's behavior. Some times the keyboard works for a little while, most of the time it doesn't work from the start. I tried different Fast Boot options but changing those does not help.

Anyone here with similar problems or who even solved this for his systems?