Dust-like objects appear to cross the screen in the depth image

Hello, I’m using Femto Mega.
In the depth image, something like dust appears to be moving across the screen.
In the example image below, something like debris is moving from top to bottom in the center of the depth image.
In reality, such an object does not exist, and it is not visible in the IR image.
The same result occurs in both OrbbecView and k4aviewer.
What could be the possible cause?
The firmware version is 1.2.8.


Not sure if it’s of any help, but i see these too on the Femto Bolt, and with the original Azure Kinekt sensors from time to time.

I see.
This is the first time I’ve seen it.