Dynamic airflow changes?

I've never seen this before but, the car was without issue for 3 months, had and accident and the loom was repaired. Its a retrofit. The fuel trims swing after a period of time, the airflow calculation changes at the same given MAP RPM and throttle position. The attached log at shows from 4.46 where the swing occurs, the car goes from +20 fuel trims to -10 and the airflow changes from 15-11 g/s. It happens mostly in all the lower air flow areas but will alter and have a 30-40% swing in trims. It does it MAF or VVE SD and Blended.

The tune is incomplete as I have been trying to work out what the.

Not sure where to look at it looks like a calculation error bey the ecu works in another car fine, thinking earth?