Weird optical flow output w.r.t. older implementations of NVOF

I used the NVIDIA Optical Flow SDK almost an year ago with great satisfaction. Some days ago I got access to a new machine equipped with an RTX 3080 GPU and I decided to try the new version 2.0 using latest OpenCV.

However, it seems that the performance, at least for my scenario, became worst.

Given a frame with static background and a moving object (held by a person whose arm is part of the scene), the output of the NVOF 1.0 one year ago on a mobile RTX 2080 was the following:

Instead, using the new RTX 3080 and latest OpenCV and NVIDIA drivers I am getting totally different result.

This is the output of the NVIDIA Optical Flow 1.0 on the new configuration

and this is the output when using version 2.0 with per-pixel precision

While the flow associated to the object seems right, the static background that was almost white in the past now is full of non-zero flow vectors (even with huge magnitudes).

How is it possible? Can I do something to get back the old results (that were looking much better to me)?

Any news about it?

Can you share pair of input frames that you used? Which application you used to generate these results? We will like to reproduce this at our end and investigate.