Altitude hold not stable using LPE with px4flow

Using pixhawk, whether using latest stable build or master build, altitude hold is not working properly.
Right after switching to altitude hold mode, drone starts stair down like descending.
Below is a log when this happens.

As you can see in the plot below, the drone does not keep the altitude and saw like movements.

When running with APM, there is no problem flying in altitude hold mode.
Is there any reason doing this?


Altitude hold problem partially solved by setiing LPE_FUSION as 160 which is setting “pub agl as lpos down” and “fuse baro”
This makes pos z estimation upside down however this seems to work now.
I also enbaled SENS_EN_LL40LS as PWM input for altitude estimation.
I finally get some stability however it is not as stable as expected. Below is the log I gathered.

What else should I look at?

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