Bad GPS healthy and pos_vert_agl is off

When using pixhawk-v3 with arducopter 3.6.10 (Firmware: px4-v2) , I got constantly flag of EKF, and two flags are off,(const_pos_mode off , pos_vert_agl off), as in the picture. and the Missplanner is usually shows: Bad GPS signal healthy. ( Number of satellites is 22/23)
But pos_vert_agl is on , and GPS is ok, in arducopter 3.5.x.

I found something that const_pos_mode is on at first. when MP shows EKF2 IMU0 IS USING GPS, EKF2 IMU1 IS USING GPS, const_pos_mode is off at the sametime and never is on.

And when the copter flied in althold,poshold and others(but stabilize),it up and down, unstabilize.Is it becase pos_vert_agl is off?