Sudden Yaw and aggressive throttle pickup at very less throttle input like 25%

Problem:
My quadcopter suddenly pickups throttle at just 15-25% throttle input and goes into full 360 rotation in clockwise direction as it becomes airborne. I usually cut off the throttle as soon as it goes airborne(since scared of being flying away)…

Build:
navio Flight Controller running 3.3 firmware
FS-TH9X 2.4GHz 9CH Upgrade Transmitter with FS-IA10B Receiver
No GPS/Compass
only stablise flight mode
4x t-motor 420kv motors with 80A ESC’s
6S lipo, 10000mah battery
Tarot 680 carbon frame
Configured using MissionPlanner

Things I’ve Tried So Far:
Re-calibrated the compass
Verified motors are level
Verified props are installed correctly and spinning the correct direction
Attempted to “trim it out” by moving yaw trim all the way to the right, didn’t put a dent in the spin

Background:
navio perfectly controls my 450mm wheelbase copter and we fly it using motion capture system and it flies very good and stable.

the 680mm wheelbase drone got crashed couple of times because of faulty pixhawk (some crapy manufacturing) later i shifted to navio, tested each motor and esc individually everything is working fine.

P.S navio is just a pixhawk sitting on raspi and nothing to do with raspi capabilities…and i am using raspi 3B+ (just for info)

Regards,
Prem