Take off Speed is too fast

Push the oil valve halfway, but the output to the motor is only increased by less than 5% from the ground station. After halfway, the output to the motor will suddenly increase by about 80%. That is, the throttle will suddenly increase after the rocker goes beyond a certain limit. However, the remote control signal received from the ground station is also normal and continuous (at least not as abrupt as the motor output). What might cause such problems?

My firmware is V3.4.3, QUAD.

I’d appreciate it if you could help me with that.