Optical flow dropouts

[JMshare]

Describe the bug
Flying with a quadcopter around 1m above ground in position control mode using optical flow, there is lot of dropouts in the optical flow data. This demonstrates by random drifts of the quadcopter in the air. As a result the position control is not reliable and I have to always correct it as I would in the altitude control mode. Is this normal due to the nature of the optical flow sensor, software issue or a question of settings?
https://review.px4.io/plot_app?log=0981a35a-deff-40ba-912a-3eda59cef16d

Flying even closer to the ground, the dropouts are even more pronounced and the px4 switches itself into altitude control mode.
https://review.px4.io/plot_app?log=406b395a-0133-4683-8ca1-7a65e748e052

To Reproduce
Pixhawk 4 fmu_v5 v1.9.0 stable
quadrotor x in position control mode

Expected behavior
I would want the position to be stable without dropouts

Log Files and Screenshots

Ground surface:

Seen by the sensor from 1m distance:

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

Closing as stale.