Adaptive subdivision displacement gets multiplied at each frame of a render

Hi, I have a very simple setup, a plane with asphalt textures, displacement in the material, and adaptive subdivs on the plane. everything is perfectly setup on a single frame.
But, when rendering animation, at each new frame the scale value of the displacement seems to add itself up, basically the darkest part of the asphalt are gone 5 feet below the ground after 40 frames of render.
I though it could be the mid-level of the disp node in the material that was set to .45, but even at .5 it does this.
Here is a video of the issue:

Basically this bottom part is just a flat plane, it should stay a flat plane with a very fine displacement, but its disp scale seems to “explode” increasing at each frame.
This is 2.93.
Thanks for anyone having a clue about this !

Rendered in 2.9 it behaves normaly:

Alrighty, seems to have been fixed in 2.93.5 !