Tricopter Vtol weird Yaw during hover

ive recently made two model Y- type Tri-copter vtol
rear motor is fixed

1st model - basically wingtra like frame with rear motor
but was facing model keeps yawing left and right

2nd model 1300 mm wingspan with 5010 motor
still some yaw issue

can anyone help me with this yawing problem

link to a video

so far I’ve tried decreasing incresinh