One-background-per-display does not work with nvidia drivers + modesetting enabled

[Ten0]

I'm running on NixOS with nvidia drivers, prime (~= optimus) and modesetting, and i3:

services.xserver.videoDrivers = [ "nvidia" "modesetting" ]; # Nvidia + Modesetting
  hardware.opengl.enable = true;
  hardware.nvidia = {
    prime = {
      # Auto share between nvidia GPU and amd GPU
      sync.enable = true;
      amdgpuBusId = "PCI:5:0:0";
      nvidiaBusId = "PCI:1:0:0";
    };
    modesetting.enable = true;
  };

Setting background with feh ignores the multi-display and sets a single image across both monitors.

feh --bg-fill --no-fehbg --random -v .

Disabling either nvidia drivers or modesetting makes it work properly.

feh version: 3.10.1

> feh -v
Compile-time switches: curl exif inotify verscmp xinerama
> xrandr --listactivemonitors
Monitors: 2
 0: +*eDP-1 1920/344x1080/193+0+0  eDP-1
 1: +HDMI-1 2560/597x1440/336+1920+0  HDMI-1

Any idea how I could investigate this?
Thanks,