I have the same problem with a Keylab 88 Mk II in the UK, even after it has been serviced by the UK distributor: velocity values are consistently uneven.
To reproduce the problem, I play a cluster of notes using the spine of a hardback book with the faulty note in the centre. Without exception, the faulty note sends a velocity value about 9% higher than all other notes. Unfortunately, there are many such notes on my controller, which makes it of little practical use.
I am working with Arturia to find a solution, but as I have a second Keylab 88 Mk II that exhibits exactly the same issue, I would be very wary of recommending this product until a solution is found. Thankfully, the product is under warranty.