3D FFT Denoiser renders partially garbage output in 22.08.1

See bottom-right corner: Left side is original, right side has 3D FFT Denoiser applied

To reproduce:

1. Open effects-grain-and-noise-20.12.1.kdenlive from erjiang/kdenlive-backcompat
2. Render out the project in both versions listed above
3. See that the version rendered by 22.08.1 has some garbage rows in the 3D FFT Denoiser clip.

Tested with kdenlive-20.12.1c-x86_64.appimage, kdenlive-22.08.1-x86_x64.AppImage on Ubuntu 22.04.