Uncontrolled yaw Qloiter

Upgraded my VTOL to 4.2.2 from 4.1.7 ( 30 + flights ) first flight after upgrade.
T -Tail 4 x T - Motor U5 & Alpha ESC
take off in Qloiter fine then cruise then loiter couple of turns then Qhover all fine then Qloiter to land, constant ccw yaw, no stick inputs quick decent held position but very fast constant yaw. noticed that motor 1 was at 1300 PWM and motor 2 was at max 1950 PWM throughout the yaw. I have bench tested the motors under load fine. The FC was sending signals to the ccw motors min & max dont have a clue as to why. Can any one help me. Here are the Tlog Data flash log and the VTOL params. The logs are long they start at 68%
Here is the google drive link to the logs and params

See Grounding Issues arduplane 4.2