Changing background wallpaper with idump only changes fb0 when attempting to change for fb1

[jimboy-701]

I'm using a Raspberry Pie 4 setup with both framebuffers enabled for hdmi outputs 1 & 2.
I've also remapped my ttys so that tty1 is set to fb0 and tty2 is set to fb1.

When running the following command in tty1 seems to work and background changes as expected.
$ idump /path/to/wallpaper.png; tput civis; YAFT="wall" FRAMEBUFFER="/dev/fb0" yaft

However when running this command in tty2 only tty1 background is changed.
$ idump /path/to/wallpaper.png; tput civis; YAFT="wall" FRAMEBUFFER="/dev/fb1" yaft

After running the command to change tty2\fb1 background then fb0 screen seems to start glitching also.