Dead zone after 50% increase

Hello everyone, please help me figure out the dead zone on the controller. The problem is that when the stick deviates from the center by more than 50%, the speed does not increase, that is, 0-50% of the active zone scale, 51-100% is inactive (I control ground equipment from the remote control, the values ​​​​on the remote control change 0-100% of the indicator, in the VESC program in the PPM display section it is the same for everyone 0-100%. But in life it seems that the speed increases by 50% and does not increase further, help with advice on where to look

Motor type: BLDC/FOC; Sensortype: Hall Sensor; Controller: tx12 (ppm signal)