I've got the same problem with my Keylab MK2, also the first encoder/knob, it's flimsy and not working properly feels like there is some loose connection. also, the c key before the global d is half working i need to press really hard to make it work. It's 2-month-old and has been like that from the beginning, I'm very careful with my instruments, don't smoke etc and only use it twice a month at home. I did try al settings in midi control center.
Is there any way i can repair it my self like cleaning behind the c key because I've of cause threw the box out the day I've received the keyboard so it's going to be difficult to send it back.