No idea about that Asus thing though.
To make it clear, the Asus is a professional pc-monitor.
Quotehttps://www.asus.com/displays-deskt…display-pa328q/
Be immersed in stunning 4K/UHD visuals with the PA328Q. It is equipped with DisplayPort 1.2, mini-DisplayPort 1.2, two HDMI ports, and a HDMI-1 / MHL 3.0 port*. PA328Q supports 4K/UHD content playback at 60Hz through HDMI-1 port or DisplayPort 1.2
1. HDMI-1 port supports 4K/UHD playback at 60Hz and the YCbCr 4:2:0 color format
2. HDMI-2, HDMI-3, and MHL 3.0 ports support 4K/UHD playback at 30Hz
Since the monitor supports YCbCr 4:2:0 only, I am guessing, that the enigma-box AX HD61 supports YCbCr 4:2:0 and therefore it works.