MPC Studio: Distorted Display when using MTC sync

Hi,
I have the problem, that everytime I activate sync via MIDI (MTC) the display at the hardware unit gets only partial updates. As a result, after a couple of tasks, I can't read anything. The problem only occurs when

- Try to sync external gear and
- The MPC MIDI-OUT is activated

If I connect something via USB-MIDI, everything is fine. That is OK at home, but playing live I want to sync some gear without USB connections - then it s____!
At Akai they tried a new mainboard (HW unit), but that does not solve the issue. I tried different computers & cables and would like to hear, if anybody else had similar experiences...

Do you get LCD screen corruption, or does it fail to update quickly/real time?

I get LCD screen corruption. It is like sometimes the last 20% of the Screen did not get an update, the next Action wouldn't Change the middle 10% and so on. After some Actions, the Display is a mess.
If I turn the Controller off and on again, it is fine for some time. But then I loose MIDI sync...
If I disable MTC send, I have no problems. But that is not an Option, because the MPC is the sequncer and the master device.
Akai already changed the Mainboard of the device. And yes, I tried different Computer and cables: from Notebooks to Desktops, from USB 2.0 to USB 3.0 and half a dozend different cables.