Hi,
i logged my 1.8t AGU (M3.83) with the Innovate LM2 hand held device and used the ecu-to-cluster RPM Signal.
What can cause this rpm issues. Its the black line with flat tops and drops.
I have a similar connection but with an Innovate SSI4, and I used a 2KOhm resistor as pull-up to clean the signal and have the best shape possible. I confirm it with an oscilloscope. Did you use or try with it?